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  • Coherence Query Performance in Large Clusters

    - by jpurdy
    Large clusters (measured in terms of the number of storage-enabled members participating in the largest cache services) may introduce challenges when issuing queries. There is no particular cluster size threshold for this, rather a gradually increasing tendency for issues to arise. The most obvious challenges are that a client's perceived query latency will be determined by the slowest responder (more likely to be a factor in larger clusters) as well as the fact that adding additional cache servers will not increase query throughput if the query processing is not compute-bound (which would generally be the case for most indexed queries). If the data set can take advantage of the partition affinity features of Coherence, then the application can use a PartitionedFilter to target a query to a single server (using partition affinity to ensure that all data is in a single partition). If this can not be done, then avoiding an excessive number of cache server JVMs will help, as will ensuring that each cache server has sufficient CPU resources available and is also properly configured to minimize GC pauses (the most common cause of a slow-responding cache server).

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  • How Do I Rollout WP-Cache To 1000 WordPress Blogs?

    - by Volomike
    My client has 1000 WordPress blogs hosted on a server for customers. Each one is in its own domain through cpanel and SuPHP, running in CGI mode on Apache2.2. Now he wants me (I'm the PHP programmer) to get WP-Cache loaded out on each of these blogs and not just activated, but enabled. He also wants the timeout value set to 2 days instead of the default setting. I have root on LAMP. What is the preferred way to roll out an update to each blog such that on a page view, it sees if WP-Cache is enabled or not. If not, it needs to copy it out from a central source, activate it, and then enable it along with the different timeout value being used.

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  • Can a proxy server cache SSL GETs? If not, would response body encryption suffice?

    - by Damian Hickey
    Can a (||any) proxy server cache content that is requested by a client over https? As the proxy server can't see the querystring, or the http headers, I reckon they can't. I'm considering a desktop application, run by a number of people behind their companies proxy. This application may access services across the internet and I'd like to take advantage of the in-built internet caching infrastructure for 'reads'. If the caching proxy servers can't cache SSL delivered content, would simply encrypting the content of a response be a viable option? I am considering all GET requests that we wish to be cachable be requested over http with the body encrypted using asymmetric encryption, where each client has the decryption key. Anytime we wish to perform a GET that is not cachable, or a POST operation, it will be performed over SSL.

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  • Basic memcached question

    - by Aadith
    I have been reading up on distributed hashing. I learnt that consistent hashing is used for distributing the keys among cache machines. I also learnt that, a key is duplicated on mutiple caches to handle failure of cache hosts. But what I have come across on memcached doesn't seem to be in alignment with all this. I read that all cache nodes are independent of each other and that if a cache goes down, requests go to DB. Theres no mention of cache miss on a host resulting in the host directing the request to another host which could either be holding the key or is nearer to the key. Can you please tell me how these two fit together? Is memcached a very preliminary form of distributed hashing which doesnt have much sophistication?

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  • J2EE/EJB + service locator: is it safe to cache EJB Home lookup result ?

    - by Guillaume
    In a J2EE application, we are using EJB2 in weblogic. To avoid losing time building the initial context and looking up EJB Home interface, I'm considering the Service Locator Pattern. But after a few search on the web I found that event if this pattern is often recommended for the InitialContext caching, there are some negative opinion about the EJB Home caching. Questions: Is it safe to cache EJB Home lookup result ? What will happen if one my cluster node is no more working ? What will happen if I install a new version of the EJB without refreshing the service locator's cache ?

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  • In Linux, how can I completely disregard the contents of /etc/ld.so.cache?

    - by BillyBBone
    Hi, For the purposes of prototyping a new set of shared libraries in a development sandbox (to which I don't have root access), I'd like to know how to execute a binary while completely overriding the contents of /etc/ld.so.cache, so that none of the system libraries get loaded. How can this be done? I have looked at mechanisms like setting the LD_LIBRARY_PATH environment variable or launching the program wrapped inside /lib/ld-linux.so, but these methods all seem to supplement the loading of libraries from /etc/ld.so.cache, but not override it completely. Help?

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  • Hold most of the object in cache/memory insted of database?

    - by feiroox
    Hi All, It just occurred to me why not to have most of the objects in a cache(memory) when an application start. if it's not that large web application. Or to have a settings for how much I want to put in the cache/memory. I just guess it could require to have something like below 1 GB RAM or a lot less. Everything in order to speed up the application even more by not querying database. Is it good idea?

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  • how to force drupal function to not use DB cache?

    - by Alaa
    Hi All, i have a module and i am using node_load(array('nid' = arg(1))); now the problem is that this function keep getting its data for node_load from DB cache. how can i force this function to not use DB cache? Example my link is http://mydomain.com/node/344983 now: $node=node_load(array('nid'=arg(1)),null,true); echo $node-nid; output 435632 which is a randomly node id (available on the system) and everytime i ctrl+F5 my browser i get new nid!! Thanks for your help

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  • Tell browsers to cache until last modified date changes?

    - by Chad Johnson
    My web site consists of static HTML files which are usually republished once per day, and sometimes more. I'm using Apache. In the vhost settings for my site, I'd like to tell browsers to cache HTML files indefinitely, until Apache sees that they are modified. So as soon as an HTML file is changed, Apache should immediately begin telling browsers it's changed and send the updated file. As soon as a new file is published, browsers should immediately begin receiving that...they should never receive old versions of files. Maybe ExpiresByType text/html modification and no "plus x days." Is something like this possible?

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  • Hide Drive / Avoid Low Diskspace Warning on ReadyBoost Cache?

    - by Simon Richter
    I've just added an SSD as a ReadyBoost cache drive, and have two minor cosmetic issues with it: the drive still shows up in the drive list I get a warning balloon every five minutes that the drive is full and that I should empty the Recycle Bin. The former is ignorable (and I guess I can solve it with a group policy); the latter is somewhat going on my nerves. Are there official buttons "hide ReadyBoost drives" and "do not warn on low diskspace for ReadyBoost drives" somewhere that I may have missed? If not, I guess I can use the group policy to hide the drive; I'd still need a way for the system to not warn about the drive being full. Also, am I right that I need to assign a drive letter and format the drive with NTFS to use it for ReadyBoost, or is there a way to just use the raw device?

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  • Cannot get nscd to run. DNS cache stale as a result

    - by Phunt
    I'm trying to troubleshoot an issue on a MediaTemple server (running CentOS5) where the DNS cache has grown stale - I think because nscd has crashed. I've tried restarting nscd: # service nscd restart Stopping nscd: [FAILED] Starting nscd: [ OK ] This makes sense since I believe nscd has crashed so it shouldn't already be running, but When I view the status of nscd: # service nscd status nscd dead but subsys locked And ps -A returns no processes related to nscd (I assume because it's dead). I've edited /etc/nscd.conf and uncommented the line that defines the location for the log file. It created the file but it never writes anything to it. I tried looking at the init script but found that it's no help since the script thinks everything is running fine - the service returns that it started up correctly. How do I 'unlock' the subsys that nscd is complaining about?

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  • How do I purge or empty Windows Explorer's network username and sharename cache?

    - by Abel
    While troubleshooting a Samba vs Windows Network issue, I noticed that Windows' Explorer remembers login credentials of remote shares, even if you ask it not to. For instance, after accessing a share using \\servername\sharename plus entering username/password and then closing Windows Explorer, adding the same share as a network drive gives the following message, regardless whether the username is the same or not: The network folder specified is currently mapped using a different user name and password. To connect using a different user name and password, first disconnect any existing mappings to this network share. Using NET USE does not show the share. After restarting the computer, I have no problems accessing the share using different credentials. But restarting just for testing other credentials is annoying, esp. while troubleshooting. How can I purge this cache, using Windows Vista? Note: using nbtstat -R[R], ipconfig /renew, killing explorer.exe or disabling / re-enabling the network card didn't help.

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  • Caching for database questions.

    - by SeanD
    When we say caching like using memcahe or Redis, is this a 1:1 caching between the user and the cache or can we cache 1 item and use it for all user? Some items like a Friend list will be 1:1 a that is unique per user. But if i want to cache the auto complete list for city lookups which can be used by any user, will it just store 1 list in the cache used by all users at same time or doe it need to store 1 list per user? Is it possible to cache the entire database, all the lookups, all the users, all their photos, etc using memache or redis? So from the above example: a friend list will be cleared from the cache when the user logs off. But something like city auto complete will stay in the cache 24-7-365, am i correct?

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  • SSIS Lookup component tuning tips

    - by jamiet
    Yesterday evening I attended a London meeting of the UK SQL Server User Group at Microsoft’s offices in London Victoria. As usual it was both a fun and informative evening and in particular there seemed to be a few questions arising about tuning the SSIS Lookup component; I rattled off some comments and figured it would be prudent to drop some of them into a dedicated blog post, hence the one you are reading right now. Scene setting A popular pattern in SSIS is to use a Lookup component to determine whether a record in the pipeline already exists in the intended destination table or not and I cover this pattern in my 2006 blog post Checking if a row exists and if it does, has it changed? (note to self: must rewrite that blog post for SSIS2008). Fundamentally the SSIS lookup component (when using FullCache option) sucks some data out of a database and holds it in memory so that it can be compared to data in the pipeline. One of the big benefits of using SSIS dataflows is that they process data one buffer at a time; that means that not all of the data from your source exists in the dataflow at the same time and is why a SSIS dataflow can process data volumes that far exceed the available memory. However, that only applies to data in the pipeline; for reasons that are hopefully obvious ALL of the data in the lookup set must exist in the memory cache for the duration of the dataflow’s execution which means that any memory used by the lookup cache will not be available to be used as a pipeline buffer. Moreover, there’s an obvious correlation between the amount of data in the lookup cache and the time it takes to charge that cache; the more data you have then the longer it will take to charge and the longer you have to wait until the dataflow actually starts to do anything. For these reasons your goal is simple: ensure that the lookup cache contains as little data as possible. General tips Here is a simple tick list you can follow in order to tune your lookups: Use a SQL statement to charge your cache, don’t just pick a table from the dropdown list made available to you. (Read why in SELECT *... or select from a dropdown in an OLE DB Source component?) Only pick the columns that you need, ignore everything else Make the database columns that your cache is populated from as narrow as possible. If a column is defined as VARCHAR(20) then SSIS will allocate 20 bytes for every value in that column – that is a big waste if the actual values are significantly less than 20 characters in length. Do you need DT_WSTR typed columns or will DT_STR suffice? DT_WSTR uses twice the amount of space to hold values that can be stored using a DT_STR so if you can use DT_STR, consider doing so. Same principle goes for the numerical datatypes DT_I2/DT_I4/DT_I8. Only populate the cache with data that you KNOW you will need. In other words, think about your WHERE clause! Thinking outside the box It is tempting to build a large monolithic dataflow that does many things, one of which is a Lookup. Often though you can make better use of your available resources by, well, mixing things up a little and here are a few ideas to get your creative juices flowing: There is no rule that says everything has to happen in a single dataflow. If you have some particularly resource intensive lookups then consider putting that lookup into a dataflow all of its own and using raw files to pass the pipeline data in and out of that dataflow. Know your data. If you think, for example, that the majority of your incoming rows will match with only a small subset of your lookup data then consider chaining multiple lookup components together; the first would use a FullCache containing that data subset and the remaining data that doesn’t find a match could be passed to a second lookup that perhaps uses a NoCache lookup thus negating the need to pull all of that least-used lookup data into memory. Do you need to process all of your incoming data all at once? If you can process different partitions of your data separately then you can partition your lookup cache as well. For example, if you are using a lookup to convert a location into a [LocationId] then why not process your data one region at a time? This will mean your lookup cache only has to contain data for the location that you are currently processing and with the ability of the Lookup in SSIS2008 and beyond to charge the cache using a dynamically built SQL statement you’ll be able to achieve it using the same dataflow and simply loop over it using a ForEach loop. Taking the previous data partitioning idea further … a dataflow can contain more than one data path so why not split your data using a conditional split component and, again, charge your lookup caches with only the data that they need for that partition. Lookups have two uses: to (1) find a matching row from the lookup set and (2) put attributes from that matching row into the pipeline. Ask yourself, do you need to do these two things at the same time? After all once you have the key column(s) from your lookup set then you can use that key to get the rest of attributes further downstream, perhaps even in another dataflow. Are you using the same lookup data set multiple times? If so, consider the file caching option in SSIS 2008 and beyond. Above all, experiment and be creative with different combinations. You may be surprised at what works. Final  thoughts If you want to know more about how the Lookup component differs in SSIS2008 from SSIS2005 then I have a dedicated blog post about that at Lookup component gets a makeover. I am on a mini-crusade at the moment to get a BULK MERGE feature into the database engine, the thinking being that if the database engine can quickly merge massive amounts of data in a similar manner to how it can insert massive amounts using BULK INSERT then that’s a lot of work that wouldn’t have to be done in the SSIS pipeline. If you think that is a good idea then go and vote for BULK MERGE on Connect. If you have any other tips to share then please stick them in the comments. Hope this helps! @Jamiet Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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  • High Load mysql on Debian server stops every day. Why?

    - by Oleg Abrazhaev
    I have Debian server with 32 gb memory. And there is apache2, memcached and nginx on this server. Memory load always on maximum. Only 500m free. Most memory leak do MySql. Apache only 70 clients configured, other services small memory usage. When mysql use all memory it stops. And nothing works, need mysql reboot. Mysql configured use maximum 24 gb memory. I have hight weight InnoDB bases. (400000 rows, 30 gb). And on server multithread daemon, that makes many inserts in this tables, thats why InnoDB. There is my mysql config. [mysqld] # # * Basic Settings # default-time-zone = "+04:00" user = mysql pid-file = /var/run/mysqld/mysqld.pid socket = /var/run/mysqld/mysqld.sock port = 3306 basedir = /usr datadir = /var/lib/mysql tmpdir = /tmp language = /usr/share/mysql/english skip-external-locking default-time-zone='Europe/Moscow' # # Instead of skip-networking the default is now to listen only on # localhost which is more compatible and is not less secure. # # * Fine Tuning # #low_priority_updates = 1 concurrent_insert = ALWAYS wait_timeout = 600 interactive_timeout = 600 #normal key_buffer_size = 2024M #key_buffer_size = 1512M #70% hot cache key_cache_division_limit= 70 #16-32 max_allowed_packet = 32M #1-16M thread_stack = 8M #40-50 thread_cache_size = 50 #orderby groupby sort sort_buffer_size = 64M #same myisam_sort_buffer_size = 400M #temp table creates when group_by tmp_table_size = 3000M #tables in memory max_heap_table_size = 3000M #on disk open_files_limit = 10000 table_cache = 10000 join_buffer_size = 5M # This replaces the startup script and checks MyISAM tables if needed # the first time they are touched myisam-recover = BACKUP #myisam_use_mmap = 1 max_connections = 200 thread_concurrency = 8 # # * Query Cache Configuration # #more ignored query_cache_limit = 50M query_cache_size = 210M #on query cache query_cache_type = 1 # # * Logging and Replication # # Both location gets rotated by the cronjob. # Be aware that this log type is a performance killer. #log = /var/log/mysql/mysql.log # # Error logging goes to syslog. This is a Debian improvement :) # # Here you can see queries with especially long duration log_slow_queries = /var/log/mysql/mysql-slow.log long_query_time = 1 log-queries-not-using-indexes # # The following can be used as easy to replay backup logs or for replication. # note: if you are setting up a replication slave, see README.Debian about # other settings you may need to change. #server-id = 1 #log_bin = /var/log/mysql/mysql-bin.log server-id = 1 log-bin = /var/lib/mysql/mysql-bin #replicate-do-db = gate log-bin-index = /var/lib/mysql/mysql-bin.index log-error = /var/lib/mysql/mysql-bin.err relay-log = /var/lib/mysql/relay-bin relay-log-info-file = /var/lib/mysql/relay-bin.info relay-log-index = /var/lib/mysql/relay-bin.index binlog_do_db = 24avia expire_logs_days = 10 max_binlog_size = 100M read_buffer_size = 4024288 innodb_buffer_pool_size = 5000M innodb_flush_log_at_trx_commit = 2 innodb_thread_concurrency = 8 table_definition_cache = 2000 group_concat_max_len = 16M #binlog_do_db = gate #binlog_ignore_db = include_database_name # # * BerkeleyDB # # Using BerkeleyDB is now discouraged as its support will cease in 5.1.12. #skip-bdb # # * InnoDB # # InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/. # Read the manual for more InnoDB related options. There are many! # You might want to disable InnoDB to shrink the mysqld process by circa 100MB. #skip-innodb # # * Security Features # # Read the manual, too, if you want chroot! # chroot = /var/lib/mysql/ # # For generating SSL certificates I recommend the OpenSSL GUI "tinyca". # # ssl-ca=/etc/mysql/cacert.pem # ssl-cert=/etc/mysql/server-cert.pem # ssl-key=/etc/mysql/server-key.pem [mysqldump] quick quote-names max_allowed_packet = 500M [mysql] #no-auto-rehash # faster start of mysql but no tab completition [isamchk] key_buffer = 32M key_buffer_size = 512M # # * NDB Cluster # # See /usr/share/doc/mysql-server-*/README.Debian for more information. # # The following configuration is read by the NDB Data Nodes (ndbd processes) # not from the NDB Management Nodes (ndb_mgmd processes). # # [MYSQL_CLUSTER] # ndb-connectstring=127.0.0.1 # # * IMPORTANT: Additional settings that can override those from this file! # The files must end with '.cnf', otherwise they'll be ignored. # !includedir /etc/mysql/conf.d/ Please, help me make it stable. Memory used /etc/mysql # free total used free shared buffers cached Mem: 32930800 32766424 164376 0 139208 23829196 -/+ buffers/cache: 8798020 24132780 Swap: 33553328 44660 33508668 Maybe my problem not in memory, but MySQL stops every day. As you can see, cache memory free 24 gb. Thank to Michael Hampton? for correction. Load overage on server 3.5. Maybe hdd or another problem? Maybe my config not optimal for 30gb InnoDB ? I'm already try mysqltuner and tunung-primer.sh , but they marked all green. Mysqltuner output mysqltuner >> MySQLTuner 1.0.1 - Major Hayden <[email protected]> >> Bug reports, feature requests, and downloads at http://mysqltuner.com/ >> Run with '--help' for additional options and output filtering -------- General Statistics -------------------------------------------------- [--] Skipped version check for MySQLTuner script [OK] Currently running supported MySQL version 5.5.24-9-log [OK] Operating on 64-bit architecture -------- Storage Engine Statistics ------------------------------------------- [--] Status: -Archive -BDB -Federated +InnoDB -ISAM -NDBCluster [--] Data in MyISAM tables: 112G (Tables: 1528) [--] Data in InnoDB tables: 39G (Tables: 340) [--] Data in PERFORMANCE_SCHEMA tables: 0B (Tables: 17) [!!] Total fragmented tables: 344 -------- Performance Metrics ------------------------------------------------- [--] Up for: 8h 18m 33s (14M q [478.333 qps], 259K conn, TX: 9B, RX: 5B) [--] Reads / Writes: 84% / 16% [--] Total buffers: 10.5G global + 81.1M per thread (200 max threads) [OK] Maximum possible memory usage: 26.3G (83% of installed RAM) [OK] Slow queries: 1% (259K/14M) [!!] Highest connection usage: 100% (201/200) [OK] Key buffer size / total MyISAM indexes: 1.5G/5.6G [OK] Key buffer hit rate: 100.0% (6B cached / 1M reads) [OK] Query cache efficiency: 74.3% (8M cached / 11M selects) [OK] Query cache prunes per day: 0 [OK] Sorts requiring temporary tables: 0% (0 temp sorts / 247K sorts) [!!] Joins performed without indexes: 106025 [!!] Temporary tables created on disk: 49% (351K on disk / 715K total) [OK] Thread cache hit rate: 99% (249 created / 259K connections) [!!] Table cache hit rate: 15% (2K open / 13K opened) [OK] Open file limit used: 15% (3K/20K) [OK] Table locks acquired immediately: 99% (4M immediate / 4M locks) [!!] InnoDB data size / buffer pool: 39.4G/5.9G -------- Recommendations ----------------------------------------------------- General recommendations: Run OPTIMIZE TABLE to defragment tables for better performance MySQL started within last 24 hours - recommendations may be inaccurate Reduce or eliminate persistent connections to reduce connection usage Adjust your join queries to always utilize indexes Temporary table size is already large - reduce result set size Reduce your SELECT DISTINCT queries without LIMIT clauses Increase table_cache gradually to avoid file descriptor limits Variables to adjust: max_connections (> 200) wait_timeout (< 600) interactive_timeout (< 600) join_buffer_size (> 5.0M, or always use indexes with joins) table_cache (> 10000) innodb_buffer_pool_size (>= 39G) Mysql primer output -- MYSQL PERFORMANCE TUNING PRIMER -- - By: Matthew Montgomery - MySQL Version 5.5.24-9-log x86_64 Uptime = 0 days 8 hrs 20 min 50 sec Avg. qps = 478 Total Questions = 14369568 Threads Connected = 16 Warning: Server has not been running for at least 48hrs. It may not be safe to use these recommendations To find out more information on how each of these runtime variables effects performance visit: http://dev.mysql.com/doc/refman/5.5/en/server-system-variables.html Visit http://www.mysql.com/products/enterprise/advisors.html for info about MySQL's Enterprise Monitoring and Advisory Service SLOW QUERIES The slow query log is enabled. Current long_query_time = 1.000000 sec. You have 260626 out of 14369701 that take longer than 1.000000 sec. to complete Your long_query_time seems to be fine BINARY UPDATE LOG The binary update log is enabled Binlog sync is not enabled, you could loose binlog records during a server crash WORKER THREADS Current thread_cache_size = 50 Current threads_cached = 45 Current threads_per_sec = 0 Historic threads_per_sec = 0 Your thread_cache_size is fine MAX CONNECTIONS Current max_connections = 200 Current threads_connected = 11 Historic max_used_connections = 201 The number of used connections is 100% of the configured maximum. You should raise max_connections INNODB STATUS Current InnoDB index space = 214 M Current InnoDB data space = 39.40 G Current InnoDB buffer pool free = 0 % Current innodb_buffer_pool_size = 5.85 G Depending on how much space your innodb indexes take up it may be safe to increase this value to up to 2 / 3 of total system memory MEMORY USAGE Max Memory Ever Allocated : 23.46 G Configured Max Per-thread Buffers : 15.84 G Configured Max Global Buffers : 7.54 G Configured Max Memory Limit : 23.39 G Physical Memory : 31.40 G Max memory limit seem to be within acceptable norms KEY BUFFER Current MyISAM index space = 5.61 G Current key_buffer_size = 1.47 G Key cache miss rate is 1 : 5578 Key buffer free ratio = 77 % Your key_buffer_size seems to be fine QUERY CACHE Query cache is enabled Current query_cache_size = 200 M Current query_cache_used = 101 M Current query_cache_limit = 50 M Current Query cache Memory fill ratio = 50.59 % Current query_cache_min_res_unit = 4 K MySQL won't cache query results that are larger than query_cache_limit in size SORT OPERATIONS Current sort_buffer_size = 64 M Current read_rnd_buffer_size = 256 K Sort buffer seems to be fine JOINS Current join_buffer_size = 5.00 M You have had 106606 queries where a join could not use an index properly You have had 8 joins without keys that check for key usage after each row join_buffer_size >= 4 M This is not advised You should enable "log-queries-not-using-indexes" Then look for non indexed joins in the slow query log. OPEN FILES LIMIT Current open_files_limit = 20210 files The open_files_limit should typically be set to at least 2x-3x that of table_cache if you have heavy MyISAM usage. Your open_files_limit value seems to be fine TABLE CACHE Current table_open_cache = 10000 tables Current table_definition_cache = 2000 tables You have a total of 1910 tables You have 2151 open tables. The table_cache value seems to be fine TEMP TABLES Current max_heap_table_size = 2.92 G Current tmp_table_size = 2.92 G Of 366426 temp tables, 49% were created on disk Perhaps you should increase your tmp_table_size and/or max_heap_table_size to reduce the number of disk-based temporary tables Note! BLOB and TEXT columns are not allow in memory tables. If you are using these columns raising these values might not impact your ratio of on disk temp tables. TABLE SCANS Current read_buffer_size = 3 M Current table scan ratio = 2846 : 1 read_buffer_size seems to be fine TABLE LOCKING Current Lock Wait ratio = 1 : 185 You may benefit from selective use of InnoDB. If you have long running SELECT's against MyISAM tables and perform frequent updates consider setting 'low_priority_updates=1'

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  • Weighted round robins via TTL - possible?

    - by Joe Hopfgartner
    I currently use DNS round robin for load balancing, which works great. The records look like this (I have a ttl of 120 seconds) ;; ANSWER SECTION: orion.2x.to. 116 IN A 80.237.201.41 orion.2x.to. 116 IN A 87.230.54.12 orion.2x.to. 116 IN A 87.230.100.10 orion.2x.to. 116 IN A 87.230.51.65 I learned that not every ISP / device treats such a response the same way. For example some DNS servers rotate the addresses randomly or always cycle them through. Some just propagate the first entry, others try to determine which is best (regionally near) by looking at the ip address. However if the userbase is big enough (spreads over multiple ISPs etc) it balances pretty well. The discrepancies from highest to lowest loaded server hardly every exceeds 15%. However now I have the problem that I am introducing more servers into the systems, that not all have the same capacities. I currently only have 1gbps servers, but I want to work with 100mbit and also 10gbps servers too. So what I want is I want to introduce a server with 10 GBps with a weight of 100, a 1 gbps server with a weight of 10 and a 100 mbit server with a weight of 1. I used to add servers twice to bring more traffic to them (which worked nice. the bandwidth doubled almost.) But adding a 10gbit server 100 times to DNS is a bit rediculous. So I thought about using the TTL. If I give server A 240 seconds ttl and server B only 120 seconds (which is about about the minimum to use for round robin, as a lot of dns servers set to 120 if a lower ttl is specified.. so i have heard) I think something like this should occour in an ideal scenario: first 120 seconds 50% of requests get server A -> keep it for 240 seconds. 50% of requests get server B -> keep it for 120 seconds second 120 seconds 50% of requests still have server A cached -> keep it for another 120 seconds. 25% of requests get server A -> keep it for 240 seconds 25% of requests get server B -> keep it for 120 seconds third 120 seconds 25% will get server A (from the 50% of Server A that now expired) -> cache 240 sec 25% will get server B (from the 50% of Server A that now expired) -> cache 120 sec 25% will have server A cached for another 120 seconds 12.5% will get server B (from the 25% of server B that now expired) -> cache 120sec 12.5% will get server A (from the 25% of server B that now expired) -> cache 240 sec fourth 120 seconds 25% will have server A cached -> cache for another 120 secs 12.5% will get server A (from the 25% of b that now expired) -> cache 240 secs 12.5% will get server B (from the 25% of b that now expired) -> cache 120 secs 12.5% will get server A (from the 25% of a that now expired) -> cache 240 secs 12.5% will get server B (from the 25% of a that now expired) -> cache 120 secs 6.25% will get server A (from the 12.5% of b that now expired) -> cache 240 secs 6.25% will get server B (from the 12.5% of b that now expired) -> cache 120 secs 12.5% will have server A cached -> cache another 120 secs ... i think i lost something at this point but i think you get the idea.... As you can see this gets pretty complicated to predict and it will for sure not work out like this in practice. But it should definitely have an effect on the distribution! I know that weighted round robin exists and is just controlled by the root server. It just cycles through dns records when responding and returns dns records with a set propability that corresponds to the weighting. My DNS server does not support this, and my requirements are not that precise. If it doesnt weight perfectly its okay, but it should go into the right direction. I think using the TTL field could be a more elegant and easier solution - and it deosnt require a dns server that controls this dynamically, which saves resources - which is in my opinion the whole point of dns load balancing vs hardware load balancers. My question now is... are there any best prectices / methos / rules of thumb to weight round robin distribution using the TTL attribute of DNS records? Edit: The system is a forward proxy server system. The amount of Bandwidth (not requests) exceeds what one single server with ethernet can handle. So I need a balancing solution that distributes the bandwidth to several servers. Are there any alternative methods than using DNS? Of course I can use a load balancer with fibre channel etc, but the costs are rediciulous and it also increases only the width of the bottleneck and does not eliminate it. The only thing i can think of are anycast (is it anycast or multicast?) ip addresses, but I don't have the means to set up such a system.

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  • Why might a System.String object not cache its hash code?

    - by Dan Tao
    A glance at the source code for string.GetHashCode using Reflector reveals the following (for mscorlib.dll version 4.0): public override unsafe int GetHashCode() { fixed (char* str = ((char*) this)) { char* chPtr = str; int num = 0x15051505; int num2 = num; int* numPtr = (int*) chPtr; for (int i = this.Length; i > 0; i -= 4) { num = (((num << 5) + num) + (num >> 0x1b)) ^ numPtr[0]; if (i <= 2) { break; } num2 = (((num2 << 5) + num2) + (num2 >> 0x1b)) ^ numPtr[1]; numPtr += 2; } return (num + (num2 * 0x5d588b65)); } } Now, I realize that the implementation of GetHashCode is not specified and is implementation-dependent, so the question "is GetHashCode implemented in the form of X or Y?" is not really answerable. I'm just curious about a few things: If Reflector has disassembled the DLL correctly and this is the implementation of GetHashCode (in my environment), am I correct in interpreting this code to indicate that a string object, based on this particular implementation, would not cache its hash code? Assuming the answer is yes, why would this be? It seems to me that the memory cost would be minimal (one more 32-bit integer, a drop in the pond compared to the size of the string itself) whereas the savings would be significant, especially in cases where, e.g., strings are used as keys in a hashtable-based collection like a Dictionary<string, [...]>. And since the string class is immutable, it isn't like the value returned by GetHashCode will ever even change. What could I be missing? UPDATE: In response to Andras Zoltan's closing remark: There's also the point made in Tim's answer(+1 there). If he's right, and I think he is, then there's no guarantee that a string is actually immutable after construction, therefore to cache the result would be wrong. Whoa, whoa there! This is an interesting point to make (and yes it's very true), but I really doubt that this was taken into consideration in the implementation of GetHashCode. The statement "therefore to cache the result would be wrong" implies to me that the framework's attitude regarding strings is "Well, they're supposed to be immutable, but really if developers want to get sneaky they're mutable so we'll treat them as such." This is definitely not how the framework views strings. It fully relies on their immutability in so many ways (interning of string literals, assignment of all zero-length strings to string.Empty, etc.) that, basically, if you mutate a string, you're writing code whose behavior is entirely undefined and unpredictable. I guess my point is that for the author(s) of this implementation to worry, "What if this string instance is modified between calls, even though the class as it is publicly exposed is immutable?" would be like for someone planning a casual outdoor BBQ to think to him-/herself, "What if someone brings an atomic bomb to the party?" Look, if someone brings an atom bomb, party's over.

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  • Apache's htcacheclean doesn't scale: How to tame a huge Apache disk_cache?

    - by flight
    We have an Apache setup with a huge disk_cache (500.000 entries, 50 GB disk space used). The cache grows by 16 GB every day. My problem is that the cache seems to be growing nearly as fast as it's possible to remove files and directories from the cache filesystem! The cache partition is an ext3 filesystem (100GB, "-t news") on an iSCSI storage. The Apache server (which acts as a caching proxy) is a VM. The disk_cache is configured with CacheDirLevels=2 and CacheDirLength=1, and includes variants. A typical file path is "/htcache/B/x/i_iGfmmHhxJRheg8NHcQ.header.vary/A/W/oGX3MAV3q0bWl30YmA_A.header". When I try to call htcacheclean to tame the cache (non-daemon mode, "htcacheclean-t -p/htcache -l15G"), IOwait is going through the roof for several hours. Without any visible action. Only after hours, htcacheclean starts to delete files from the cache partition, which takes a couple more hours. (A similar problem was brought up in the Apache mailing list in 2009, without a solution: http://www.mail-archive.com/[email protected]/msg42683.html) The high IOwait leads to problems with the stability of the web server (the bridge to the Tomcat backend server sometimes stalls). I came up with my own prune script, which removes files and directories from random subdirectories of the cache. Only to find that the deletion rate of the script is just slightly higher than the cache growth rate. The script takes ~10 seconds to read the a subdirectory (e.g. /htcache/B/x) and frees some 5 MB of disk space. In this 10 seconds, the cache has grown by another 2 MB. As with htcacheclean, IOwait goes up to 25% when running the prune script continuously. Any idea? Is this a problem specific to the (rather slow) iSCSI storage? Should I choose a different file system for a huge disk_cache? ext2? ext4? Are there any kernel parameter optimizations for this kind of scenario? (I already tried the deadline scheduler and a smaller read_ahead_kb, without effect).

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  • NEC uPD720200 USB 3.0 not working on Ubuntu 12.04

    - by Jagged
    I've recently installed Ubuntu 12.04 64-bit on a HP Envy 15 1104tx. Most stuff appears to be working fine with the exception of the two USB3 ports (USB2 port works fine). I've read a lot of articles but so far have not been able to find a solution. I've tried adding 'pci=nomsi' to '/etc/default/grub' but this made no difference. Some articles suggest booting into Windows and upgrading the firmware on the uPD720200. Any body had any experience of this? Is there a way I can checked the firmware version of the NEC uPD720200 in Linux to see if there is an update available? Any help appreciated. uname -a: Linux HP-ENVY-15-1104tx 3.2.0-26-generic #41-Ubuntu SMP Thu Jun 14 17:49:24 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux lshw: hp-envy-15-1104tx description: Notebook product: HP ENVY 15 Notebook PC (WF591PA#ABG) vendor: Hewlett-Packard version: 0492110000241910001420000 serial: CNF0301C79 width: 64 bits capabilities: smbios-2.6 dmi-2.6 vsyscall32 configuration: boot=normal chassis=notebook family=103C_5335KV sku=WF591PA#ABG uuid=434E4630-3330-3143-3739-60EB6906688F *-core description: Motherboard product: 1522 vendor: Hewlett-Packard physical id: 0 version: 36.35 serial: CNF0301C79 slot: Base Board Chassis Location *-firmware description: BIOS vendor: Hewlett-Packard physical id: 0 version: F.2B date: 10/12/2010 size: 1MiB capacity: 1472KiB capabilities: pci upgrade shadowing cdboot bootselect edd int13floppynec int13floppytoshiba int13floppy360 int13floppy1200 int13floppy720 int13floppy2880 int9keyboard int10video acpi usb biosbootspecification *-memory description: System Memory physical id: 13 slot: System board or motherboard size: 16GiB *-bank:0 description: SODIMM DDR3 Synchronous 1333 MHz (0.8 ns) product: 9905428-043.A00LF physical id: 0 serial: E13C4316 slot: Bottom size: 4GiB width: 64 bits clock: 1333MHz (0.8ns) *-bank:1 description: SODIMM DDR3 Synchronous 1333 MHz (0.8 ns) product: 9905428-043.A00LF physical id: 1 serial: E03C3E16 slot: Bottom size: 4GiB width: 64 bits clock: 1333MHz (0.8ns) *-bank:2 description: SODIMM DDR3 Synchronous 1333 MHz (0.8 ns) product: 9905428-043.A00LF physical id: 2 serial: 672279CC slot: On Board size: 4GiB width: 64 bits clock: 1333MHz (0.8ns) *-bank:3 description: SODIMM DDR3 Synchronous 1333 MHz (0.8 ns) product: 9905428-043.A00LF physical id: 3 serial: 652286CC slot: On Board size: 4GiB width: 64 bits clock: 1333MHz (0.8ns) *-cpu description: CPU product: Intel(R) Core(TM) i7 CPU Q 820 @ 1.73GHz vendor: Intel Corp. physical id: 1d bus info: cpu@0 version: Intel(R) Core(TM) i7 CPU Q 820 @ 1.73GHz slot: CPU size: 1199MHz capacity: 1199MHz width: 64 bits clock: 1066MHz capabilities: x86-64 fpu fpu_exception wp vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 popcnt lahf_lm ida tpr_shadow vnmi flexpriority ept vpid cpufreq configuration: cores=4 enabledcores=4 threads=8 *-cache:0 description: L3 cache physical id: 1e slot: L3 Cache size: 8MiB capacity: 8MiB capabilities: synchronous internal write-through unified *-cache:1 description: L2 cache physical id: 20 slot: L2 Cache size: 256KiB capacity: 256KiB capabilities: synchronous internal write-through unified *-cache:2 description: L1 cache physical id: 21 slot: L1 Cache size: 32KiB capacity: 32KiB capabilities: synchronous internal write-through instruction *-cache description: L1 cache physical id: 1f slot: L1 Cache size: 32KiB capacity: 32KiB capabilities: synchronous internal write-through data *-pci:0 description: Host bridge product: Core Processor DMI vendor: Intel Corporation physical id: 100 bus info: pci@0000:00:00.0 version: 11 width: 32 bits clock: 33MHz *-pci:0 description: PCI bridge product: Core Processor PCI Express Root Port 1 vendor: Intel Corporation physical id: 3 bus info: pci@0000:00:03.0 version: 11 width: 32 bits clock: 33MHz capabilities: pci msi pciexpress pm normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:16 ioport:4000(size=4096) memory:d4100000-d41fffff ioport:c0000000(size=268435456) *-display description: VGA compatible controller product: Broadway PRO [Mobility Radeon HD 5800 Series] vendor: Hynix Semiconductor (Hyundai Electronics) physical id: 0 bus info: pci@0000:01:00.0 version: 00 width: 64 bits clock: 33MHz capabilities: pm pciexpress msi vga_controller bus_master cap_list rom configuration: driver=fglrx_pci latency=0 resources: irq:58 memory:c0000000-cfffffff memory:d4100000-d411ffff ioport:4000(size=256) memory:d4140000-d415ffff *-multimedia description: Audio device product: Juniper HDMI Audio [Radeon HD 5700 Series] vendor: Hynix Semiconductor (Hyundai Electronics) physical id: 0.1 bus info: pci@0000:01:00.1 version: 00 width: 64 bits clock: 33MHz capabilities: pm pciexpress msi bus_master cap_list configuration: driver=snd_hda_intel latency=0 resources: irq:56 memory:d4120000-d4123fff *-pci:1 description: PCI bridge product: Core Processor PCI Express Root Port 3 vendor: Intel Corporation physical id: 5 bus info: pci@0000:00:05.0 version: 11 width: 32 bits clock: 33MHz capabilities: pci msi pciexpress pm normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:16 memory:d4000000-d40fffff *-usb description: USB controller product: uPD720200 USB 3.0 Host Controller vendor: NEC Corporation physical id: 0 bus info: pci@0000:02:00.0 version: 03 width: 64 bits clock: 33MHz capabilities: pm msi msix pciexpress xhci bus_master cap_list configuration: driver=xhci_hcd latency=0 resources: irq:16 memory:d4000000-d4001fff *-generic:0 UNCLAIMED description: System peripheral product: Core Processor System Management Registers vendor: Intel Corporation physical id: 8 bus info: pci@0000:00:08.0 version: 11 width: 32 bits clock: 33MHz capabilities: pciexpress cap_list configuration: latency=0 *-generic:1 UNCLAIMED description: System peripheral product: Core Processor Semaphore and Scratchpad Registers vendor: Intel Corporation physical id: 8.1 bus info: pci@0000:00:08.1 version: 11 width: 32 bits clock: 33MHz capabilities: pciexpress cap_list configuration: latency=0 *-generic:2 UNCLAIMED description: System peripheral product: Core Processor System Control and Status Registers vendor: Intel Corporation physical id: 8.2 bus info: pci@0000:00:08.2 version: 11 width: 32 bits clock: 33MHz capabilities: pciexpress cap_list configuration: latency=0 *-generic:3 UNCLAIMED description: System peripheral product: Core Processor Miscellaneous Registers vendor: Intel Corporation physical id: 8.3 bus info: pci@0000:00:08.3 version: 11 width: 32 bits clock: 33MHz configuration: latency=0 *-generic:4 UNCLAIMED description: System peripheral product: Core Processor QPI Link vendor: Intel Corporation physical id: 10 bus info: pci@0000:00:10.0 version: 11 width: 32 bits clock: 33MHz configuration: latency=0 *-generic:5 UNCLAIMED description: System peripheral product: Core Processor QPI Routing and Protocol Registers vendor: Intel Corporation physical id: 10.1 bus info: pci@0000:00:10.1 version: 11 width: 32 bits clock: 33MHz configuration: latency=0 *-multimedia description: Audio device product: 5 Series/3400 Series Chipset High Definition Audio vendor: Intel Corporation physical id: 1b bus info: pci@0000:00:1b.0 version: 05 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list configuration: driver=snd_hda_intel latency=0 resources: irq:55 memory:d4200000-d4203fff *-pci:2 description: PCI bridge product: 5 Series/3400 Series Chipset PCI Express Root Port 1 vendor: Intel Corporation physical id: 1c bus info: pci@0000:00:1c.0 version: 05 width: 32 bits clock: 33MHz capabilities: pci pciexpress msi pm normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:17 ioport:3000(size=4096) memory:d3000000-d3ffffff ioport:d0000000(size=16777216) *-network description: Wireless interface product: Centrino Advanced-N 6200 vendor: Intel Corporation physical id: 0 bus info: pci@0000:03:00.0 logical name: wlan0 version: 35 serial: 00:27:10:40:e4:68 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=iwlwifi driverversion=3.2.0-26-generic firmware=9.221.4.1 build 25532 latency=0 link=no multicast=yes wireless=IEEE 802.11abgn resources: irq:54 memory:d3000000-d3001fff *-pci:3 description: PCI bridge product: 5 Series/3400 Series Chipset PCI Express Root Port 2 vendor: Intel Corporation physical id: 1c.1 bus info: pci@0000:00:1c.1 version: 05 width: 32 bits clock: 33MHz capabilities: pci pciexpress msi pm normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:16 ioport:2000(size=4096) memory:d2000000-d2ffffff ioport:d1000000(size=16777216) *-network description: Ethernet interface product: AR8131 Gigabit Ethernet vendor: Atheros Communications Inc. physical id: 0 bus info: pci@0000:04:00.0 logical name: eth0 version: c0 serial: 60:eb:69:06:68:8f size: 1Gbit/s capacity: 1Gbit/s width: 64 bits clock: 33MHz capabilities: pm msi pciexpress vpd bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=atl1c driverversion=1.0.1.0-NAPI duplex=full firmware=N/A ip=10.161.0.147 latency=0 link=yes multicast=yes port=twisted pair speed=1Gbit/s resources: irq:57 memory:d2000000-d203ffff ioport:2000(size=128) *-usb description: USB controller product: 5 Series/3400 Series Chipset USB2 Enhanced Host Controller vendor: Intel Corporation physical id: 1d bus info: pci@0000:00:1d.0 version: 05 width: 32 bits clock: 33MHz capabilities: pm debug ehci bus_master cap_list configuration: driver=ehci_hcd latency=0 resources: irq:20 memory:d4205800-d4205bff *-pci:4 description: PCI bridge product: 82801 Mobile PCI Bridge vendor: Intel Corporation physical id: 1e bus info: pci@0000:00:1e.0 version: a5 width: 32 bits clock: 33MHz capabilities: pci subtractive_decode bus_master cap_list *-isa description: ISA bridge product: Mobile 5 Series Chipset LPC Interface Controller vendor: Intel Corporation physical id: 1f bus info: pci@0000:00:1f.0 version: 05 width: 32 bits clock: 33MHz capabilities: isa bus_master cap_list configuration: latency=0 *-storage description: RAID bus controller product: 82801 Mobile SATA Controller [RAID mode] vendor: Intel Corporation physical id: 1f.2 bus info: pci@0000:00:1f.2 logical name: scsi0 version: 05 width: 32 bits clock: 66MHz capabilities: storage msi pm bus_master cap_list emulated configuration: driver=ahci latency=0 resources: irq:45 ioport:5048(size=8) ioport:5054(size=4) ioport:5040(size=8) ioport:5050(size=4) ioport:5020(size=32) memory:d4205000-d42057ff *-disk description: ATA Disk product: OCZ-VERTEX3 physical id: 0.0.0 bus info: scsi@0:0.0.0 logical name: /dev/sda version: 2.15 serial: OCZ-0350P6H316X5KUQE size: 223GiB (240GB) capabilities: partitioned partitioned:dos configuration: ansiversion=5 signature=000592dd *-volume:0 description: EXT4 volume vendor: Linux physical id: 1 bus info: scsi@0:0.0.0,1 logical name: /dev/sda1 logical name: / version: 1.0 serial: e741f18c-cfc5-4bce-b1e7-f80e517a3a22 size: 207GiB capacity: 207GiB capabilities: primary bootable journaled extended_attributes large_files huge_files dir_nlink recover extents ext4 ext2 initialized configuration: created=2012-06-15 06:49:27 filesystem=ext4 lastmountpoint=/ modified=2012-06-14 21:23:42 mount.fstype=ext4 mount.options=rw,relatime,errors=remount-ro,user_xattr,barrier=1,data=ordered mounted=2012-07-10 16:18:20 state=mounted *-volume:1 description: Extended partition physical id: 2 bus info: scsi@0:0.0.0,2 logical name: /dev/sda2 size: 15GiB capacity: 15GiB capabilities: primary extended partitioned partitioned:extended *-logicalvolume description: Linux swap / Solaris partition physical id: 5 logical name: /dev/sda5 capacity: 15GiB capabilities: nofs *-serial UNCLAIMED description: SMBus product: 5 Series/3400 Series Chipset SMBus Controller vendor: Intel Corporation physical id: 1f.3 bus info: pci@0000:00:1f.3 version: 05 width: 64 bits clock: 33MHz configuration: latency=0 resources: memory:d4205c00-d4205cff ioport:5000(size=32) *-pci:1 description: Host bridge product: Core Processor QuickPath Architecture Generic Non-Core Registers vendor: Intel Corporation physical id: 101 bus info: pci@0000:ff:00.0 version: 04 width: 32 bits clock: 33MHz *-pci:2 description: Host bridge product: Core Processor QuickPath Architecture System Address Decoder vendor: Intel Corporation physical id: 102 bus info: pci@0000:ff:00.1 version: 04 width: 32 bits clock: 33MHz *-pci:3 description: Host bridge product: Core Processor QPI Link 0 vendor: Intel Corporation physical id: 103 bus info: pci@0000:ff:02.0 version: 04 width: 32 bits clock: 33MHz *-pci:4 description: Host bridge product: Core Processor QPI Physical 0 vendor: Intel Corporation physical id: 104 bus info: pci@0000:ff:02.1 version: 04 width: 32 bits clock: 33MHz *-pci:5 description: Host bridge product: Core Processor Integrated Memory Controller vendor: Intel Corporation physical id: 105 bus info: pci@0000:ff:03.0 version: 04 width: 32 bits clock: 33MHz *-pci:6 description: Host bridge product: Core Processor Integrated Memory Controller Target Address Decoder vendor: Intel Corporation physical id: 106 bus info: pci@0000:ff:03.1 version: 04 width: 32 bits clock: 33MHz *-pci:7 description: Host bridge product: Core Processor Integrated Memory Controller Test Registers vendor: Intel Corporation physical id: 107 bus info: pci@0000:ff:03.4 version: 04 width: 32 bits clock: 33MHz *-pci:8 description: Host bridge product: Core Processor Integrated Memory Controller Channel 0 Control Registers vendor: Intel Corporation physical id: 108 bus info: pci@0000:ff:04.0 version: 04 width: 32 bits clock: 33MHz *-pci:9 description: Host bridge product: Core Processor Integrated Memory Controller Channel 0 Address Registers vendor: Intel Corporation physical id: 109 bus info: pci@0000:ff:04.1 version: 04 width: 32 bits clock: 33MHz *-pci:10 description: Host bridge product: Core Processor Integrated Memory Controller Channel 0 Rank Registers vendor: Intel Corporation physical id: 10a bus info: pci@0000:ff:04.2 version: 04 width: 32 bits clock: 33MHz *-pci:11 description: Host bridge product: Core Processor Integrated Memory Controller Channel 0 Thermal Control Registers vendor: Intel Corporation physical id: 10b bus info: pci@0000:ff:04.3 version: 04 width: 32 bits clock: 33MHz *-pci:12 description: Host bridge product: Core Processor Integrated Memory Controller Channel 1 Control Registers vendor: Intel Corporation physical id: 10c bus info: pci@0000:ff:05.0 version: 04 width: 32 bits clock: 33MHz *-pci:13 description: Host bridge product: Core Processor Integrated Memory Controller Channel 1 Address Registers vendor: Intel Corporation physical id: 10d bus info: pci@0000:ff:05.1 version: 04 width: 32 bits clock: 33MHz *-pci:14 description: Host bridge product: Core Processor Integrated Memory Controller Channel 1 Rank Registers vendor: Intel Corporation physical id: 10e bus info: pci@0000:ff:05.2 version: 04 width: 32 bits clock: 33MHz *-pci:15 description: Host bridge product: Core Processor Integrated Memory Controller Channel 1 Thermal Control Registers vendor: Intel Corporation physical id: 10f bus info: pci@0000:ff:05.3 version: 04 width: 32 bits clock: 33MHz *-battery description: Lithium Ion Battery product: NK06053 vendor: SMP-ATL24 physical id: 1 slot: Primary capacity: 4800mWh configuration: voltage=11.1V lspci: 02:00.0 USB controller: NEC Corporation uPD720200 USB 3.0 Host Controller (rev 03) (prog-if 30 [XHCI]) Subsystem: Hewlett-Packard Company Device 1522 Flags: bus master, fast devsel, latency 0, IRQ 16 Memory at d4000000 (64-bit, non-prefetchable) [size=8K] Capabilities: [50] Power Management version 3 Capabilities: [70] MSI: Enable- Count=1/8 Maskable- 64bit+ Capabilities: [90] MSI-X: Enable+ Count=8 Masked- Capabilities: [a0] Express Endpoint, MSI 00 Capabilities: [100] Advanced Error Reporting Capabilities: [140] Device Serial Number ff-ff-ff-ff-ff-ff-ff-ff Capabilities: [150] Latency Tolerance Reporting Kernel driver in use: xhci_hcd lsusb (with thumb drive plugged into USB3 port): Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 003 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 003: ID 5986:01d0 Acer, Inc Bus 001 Device 004: ID 03f0:231d Hewlett-Packard

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  • Drivers for NVIDIA 520M not working in Ubuntu 12.04

    - by Don
    I am aware that this is nominally a duplicate question, however I've read the other questions and haven't been able to resolve my problem after many hours and attempts, so please don't delete it. Additionally, it seems like many answers to the other questions are specifically dependent on certain situations. My situation being different from the others I found represented, here's my question. Until last night, I had Ubuntu 12.04 installed with Wubi, and it ran ok, though slowly and with occasional hangs. So I partitioned the drive and installed 12.04 in its own partition. Now when I start it, I am stuck using 2D. I believe this is an NVIDIA bug. My NVIDIA card is a GT 520M and my machine has Optimus. Additional Drivers only displays my wireless driver. Going to System Settings Details Graphics shows Driver:Unknown, Experience:Standard. I downloaded the driver from the NVIDIA website, and ran the installer with no errors, except that the "distribution-provided pre-install script failed". After rebooting, my screen was stuck at 640X480, which was fixed by editing /etc/X11/xorg.conf However, I still was stuck in 2D, and nothing else had changed either. A thread suggested something called Bumblebee. I tried that, and when I ran optirun firefoxI got a frozen blank screen. Following another suggestion, I checked the BIOS to try and disable Optimus. I found and ran myriad other commands to try and fix the problem and nothing changed. Now I have just done a clean re-install of Ubuntu. From there, I: Installed all the updates Downloaded the NVIDIA driver Installed it Got screen stuck at 640X480, fixed in xorg.conf. To recap the problem: I can't get the NVIDIA drivers working I am stuck using 2D I'm an idiot I think if the first one is solved, the solution to the second will naturally follow. If you need me to provide any other information, I'd be happy to. From what I've seen in other threads, I think this information may help: lsmod: dh@donsMachine:~$ lsmod Module Size Used by nvidia 12353161 0 snd_hda_codec_hdmi 32474 1 snd_hda_codec_realtek 223867 1 joydev 17693 0 parport_pc 32866 0 ppdev 17113 0 rfcomm 47604 0 bnep 18281 2 bluetooth 180104 10 rfcomm,bnep snd_hda_intel 33773 3 snd_hda_codec 127706 3 snd_hda_codec_hdmi,snd_hda_codec_realtek,snd_hda_intel snd_hwdep 13668 1 snd_hda_codec snd_pcm 97188 3 snd_hda_codec_hdmi,snd_hda_intel,snd_hda_codec uvcvideo 72627 0 videodev 98259 1 uvcvideo v4l2_compat_ioctl32 17128 1 videodev snd_seq_midi 13324 0 snd_rawmidi 30748 1 snd_seq_midi snd_seq_midi_event 14899 1 snd_seq_midi snd_seq 61896 2 snd_seq_midi,snd_seq_midi_event lib80211_crypt_tkip 17390 0 wl 2568210 0 lib80211 14381 2 lib80211_crypt_tkip,wl snd_timer 29990 2 snd_pcm,snd_seq snd_seq_device 14540 3 snd_seq_midi,snd_rawmidi,snd_seq snd 78855 16 snd_hda_codec_hdmi,snd_hda_codec_realtek,snd_hda_intel,snd_hda_codec,snd_hwdep,snd_pcm,snd_rawmidi,snd_seq,snd_timer,snd_seq_device psmouse 87692 0 serio_raw 13211 0 i915 468745 2 soundcore 15091 1 snd snd_page_alloc 18529 2 snd_hda_intel,snd_pcm drm_kms_helper 46978 1 i915 drm 242038 3 i915,drm_kms_helper mei 41616 0 i2c_algo_bit 13423 1 i915 mxm_wmi 12979 0 acer_wmi 28418 0 sparse_keymap 13890 1 acer_wmi video 19596 1 i915 wmi 19256 2 mxm_wmi,acer_wmi mac_hid 13253 0 lp 17799 0 parport 46562 3 parport_pc,ppdev,lp tg3 152032 0 sdhci_pci 18826 0 sdhci 33205 1 sdhci_pci lspci -nn | grep VGA dh@donsMachine:~$ lspci -nn | grep VGA 00:02.0 VGA compatible controller [0300]: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller [8086:0116] (rev 09) 01:00.0 VGA compatible controller [0300]: NVIDIA Corporation Device [10de:0df7] (rev a1) lshw dh@donsMachine:~$ sudo lshw [sudo] password for dh: donsmachine description: Notebook product: EasyNote TS44HR () vendor: Packard Bell version: V1.12 serial: LXBWZ02017134209D71601 width: 64 bits capabilities: smbios-2.7 dmi-2.7 vsyscall32 configuration: boot=normal chassis=notebook uuid=16FE576B-CA15-11E0-B096-B870F4E51243 *-core description: Motherboard product: SJV50_HR vendor: Packard Bell physical id: 0 version: Base Board Version serial: Base Board Serial Number slot: Base Board Chassis Location *-firmware description: BIOS vendor: Packard Bell physical id: 0 version: V1.12 date: 07/11/2011 size: 1MiB capacity: 2496KiB capabilities: pci upgrade shadowing cdboot bootselect edd int13floppynec int13floppytoshiba int13floppy360 int13floppy1200 int13floppy720 int13floppy2880 int9keyboard int10video acpi usb biosbootspecification *-memory description: System Memory physical id: 1b slot: System board or motherboard size: 4GiB *-bank:0 description: SODIMM DDR3 Synchronous 1333 MHz (0.8 ns) product: NT2GC64B88B0NS-CG vendor: Nanya Technology physical id: 0 serial: 598E126E slot: ChannelA-DIMM0 size: 2GiB width: 64 bits clock: 1333MHz (0.8ns) *-bank:1 description: DIMM [empty] physical id: 1 slot: ChannelA-DIMM1 *-bank:2 description: SODIMM DDR3 Synchronous 1333 MHz (0.8 ns) product: NT2GC64B88B0NS-CG vendor: Nanya Technology physical id: 2 serial: 159E126C slot: ChannelB-DIMM0 size: 2GiB width: 64 bits clock: 1333MHz (0.8ns) *-bank:3 description: DIMM [empty] physical id: 3 slot: ChannelB-DIMM1 *-cpu description: CPU product: Intel(R) Core(TM) i3-2330M CPU @ 2.20GHz vendor: Intel Corp. physical id: 2e bus info: cpu@0 version: Intel(R) Core(TM) i3-2330M CPU @ 2.20GHz slot: CPU1 size: 2GHz capacity: 4GHz width: 64 bits clock: 1333MHz capabilities: x86-64 fpu fpu_exception wp vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer xsave avx lahf_lm arat epb xsaveopt pln pts tpr_shadow vnmi flexpriority ept vpid cpufreq configuration: cores=2 enabledcores=2 threads=4 *-cache:0 description: L1 cache physical id: 30 slot: L1 Cache size: 32KiB capacity: 32KiB capabilities: synchronous internal write-through instruction *-cache:1 description: L2 cache physical id: 31 slot: L2 Cache size: 256KiB capacity: 256KiB capabilities: synchronous internal write-through unified *-cache:2 description: L3 cache physical id: 32 slot: L3 Cache size: 3MiB capacity: 3MiB capabilities: synchronous internal write-through unified *-cache description: L1 cache physical id: 2f slot: L1 Cache size: 32KiB capacity: 32KiB capabilities: synchronous internal write-through data *-pci description: Host bridge product: 2nd Generation Core Processor Family DRAM Controller vendor: Intel Corporation physical id: 100 bus info: pci@0000:00:00.0 version: 09 width: 32 bits clock: 33MHz configuration: driver=agpgart-intel resources: irq:0 *-pci:0 description: PCI bridge product: Xeon E3-1200/2nd Generation Core Processor Family PCI Express Root Port vendor: Intel Corporation physical id: 1 bus info: pci@0000:00:01.0 version: 09 width: 32 bits clock: 33MHz capabilities: pci pm msi pciexpress normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:40 ioport:2000(size=4096) memory:d0000000-d10fffff ioport:a0000000(size=301989888) *-display description: VGA compatible controller product: NVIDIA Corporation vendor: NVIDIA Corporation physical id: 0 bus info: pci@0000:01:00.0 version: a1 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress vga_controller bus_master cap_list rom configuration: driver=nvidia latency=0 resources: irq:16 memory:d0000000-d0ffffff memory:a0000000-afffffff memory:b0000000-b1ffffff ioport:2000(size=128) memory:d1000000-d107ffff *-display description: VGA compatible controller product: 2nd Generation Core Processor Family Integrated Graphics Controller vendor: Intel Corporation physical id: 2 bus info: pci@0000:00:02.0 version: 09 width: 64 bits clock: 33MHz capabilities: msi pm vga_controller bus_master cap_list rom configuration: driver=i915 latency=0 resources: irq:43 memory:d1400000-d17fffff memory:c0000000-cfffffff ioport:3000(size=64) *-communication description: Communication controller product: 6 Series/C200 Series Chipset Family MEI Controller #1 vendor: Intel Corporation physical id: 16 bus info: pci@0000:00:16.0 version: 04 width: 64 bits clock: 33MHz capabilities: pm msi bus_master cap_list configuration: driver=mei latency=0 resources: irq:42 memory:d1a04000-d1a0400f *-usb:0 description: USB controller product: 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #2 vendor: Intel Corporation physical id: 1a bus info: pci@0000:00:1a.0 version: 04 width: 32 bits clock: 33MHz capabilities: pm debug ehci bus_master cap_list configuration: driver=ehci_hcd latency=0 resources: irq:16 memory:d1a0a000-d1a0a3ff *-multimedia description: Audio device product: 6 Series/C200 Series Chipset Family High Definition Audio Controller vendor: Intel Corporation physical id: 1b bus info: pci@0000:00:1b.0 version: 04 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list configuration: driver=snd_hda_intel latency=0 resources: irq:44 memory:d1a00000-d1a03fff *-pci:1 description: PCI bridge product: 6 Series/C200 Series Chipset Family PCI Express Root Port 1 vendor: Intel Corporation physical id: 1c bus info: pci@0000:00:1c.0 version: b4 width: 32 bits clock: 33MHz capabilities: pci pciexpress msi pm normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:17 memory:9fb00000-9fbfffff ioport:d1800000(size=1048576) *-network description: Ethernet interface product: NetLink BCM57785 Gigabit Ethernet PCIe vendor: Broadcom Corporation physical id: 0 bus info: pci@0000:02:00.0 logical name: eth0 version: 10 serial: b8:70:f4:e5:12:43 capacity: 1Gbit/s width: 64 bits clock: 33MHz capabilities: pm msi msix pciexpress bus_master cap_list rom ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=tg3 driverversion=3.121 firmware=sb latency=0 link=no multicast=yes port=twisted pair resources: irq:16 memory:d1830000-d183ffff memory:d1840000-d184ffff memory:d1850000-d18507ff *-generic:0 description: SD Host controller product: NetXtreme BCM57765 Memory Card Reader vendor: Broadcom Corporation physical id: 0.1 bus info: pci@0000:02:00.1 version: 10 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list configuration: driver=sdhci-pci latency=0 resources: irq:17 memory:d1800000-d180ffff *-generic:1 UNCLAIMED description: System peripheral product: Broadcom Corporation vendor: Broadcom Corporation physical id: 0.2 bus info: pci@0000:02:00.2 version: 10 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list configuration: latency=0 resources: memory:d1810000-d181ffff *-generic:2 UNCLAIMED description: System peripheral product: Broadcom Corporation vendor: Broadcom Corporation physical id: 0.3 bus info: pci@0000:02:00.3 version: 10 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list configuration: latency=0 resources: memory:d1820000-d182ffff *-pci:2 description: PCI bridge product: 6 Series/C200 Series Chipset Family PCI Express Root Port 2 vendor: Intel Corporation physical id: 1c.1 bus info: pci@0000:00:1c.1 version: b4 width: 32 bits clock: 33MHz capabilities: pci pciexpress msi pm normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:16 memory:d1900000-d19fffff *-network description: Wireless interface product: BCM43225 802.11b/g/n vendor: Broadcom Corporation physical id: 0 bus info: pci@0000:03:00.0 logical name: eth1 version: 01 serial: 68:a3:c4:44:81:96 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=wl0 driverversion=5.100.82.38 ip=192.168.0.12 latency=0 multicast=yes wireless=IEEE 802.11bgn resources: irq:17 memory:d1900000-d1903fff *-usb:1 description: USB controller product: 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #1 vendor: Intel Corporation physical id: 1d bus info: pci@0000:00:1d.0 version: 04 width: 32 bits clock: 33MHz capabilities: pm debug ehci bus_master cap_list configuration: driver=ehci_hcd latency=0 resources: irq:23 memory:d1a09000-d1a093ff *-isa description: ISA bridge product: HM65 Express Chipset Family LPC Controller vendor: Intel Corporation physical id: 1f bus info: pci@0000:00:1f.0 version: 04 width: 32 bits clock: 33MHz capabilities: isa bus_master cap_list configuration: latency=0 *-storage description: SATA controller product: 6 Series/C200 Series Chipset Family 6 port SATA AHCI Controller vendor: Intel Corporation physical id: 1f.2 bus info: pci@0000:00:1f.2 logical name: scsi0 logical name: scsi1 version: 04 width: 32 bits clock: 66MHz capabilities: storage msi pm ahci_1.0 bus_master cap_list emulated configuration: driver=ahci latency=0 resources: irq:41 ioport:3098(size=8) ioport:30bc(size=4) ioport:3090(size=8) ioport:30b8(size=4) ioport:3060(size=32) memory:d1a08000-d1a087ff *-disk description: ATA Disk product: ST9500325AS vendor: Seagate physical id: 0 bus info: scsi@0:0.0.0 logical name: /dev/sda version: 0001 serial: S2W1AMSX size: 465GiB (500GB) capabilities: partitioned partitioned:dos configuration: ansiversion=5 signature=a45f21e9 *-volume:0 description: Windows NTFS volume physical id: 1 bus info: scsi@0:0.0.0,1 logical name: /dev/sda1 version: 3.1 serial: 46aa-2a25 size: 19GiB capacity: 20GiB capabilities: primary ntfs initialized configuration: clustersize=4096 created=2011-08-25 21:32:00 filesystem=ntfs label=PQSERVICE state=clean *-volume:1 description: Windows NTFS volume physical id: 2 bus info: scsi@0:0.0.0,2 logical name: /dev/sda2 version: 3.1 serial: 10aa-ad1a size: 98MiB capacity: 100MiB capabilities: primary bootable ntfs initialized configuration: clustersize=4096 created=2011-08-25 21:32:03 filesystem=ntfs label=SYSTEM RESERVED state=clean *-volume:2 description: Windows NTFS volume physical id: 3 bus info: scsi@0:0.0.0,3 logical name: /dev/sda3 version: 3.1 serial: 668c5afc-182e-ff4b-b084-3cc09f54972d size: 395GiB capacity: 395GiB capabilities: primary ntfs initialized configuration: clustersize=4096 created=2011-08-25 21:32:03 filesystem=ntfs label=Don's Machine state=clean *-volume:3 description: Extended partition physical id: 4 bus info: scsi@0:0.0.0,4 logical name: /dev/sda4 size: 49GiB capacity: 49GiB capabilities: primary extended partitioned partitioned:extended *-logicalvolume:0 description: Linux swap / Solaris partition physical id: 5 logical name: /dev/sda5 capacity: 3945MiB capabilities: nofs *-logicalvolume:1 description: Linux filesystem partition physical id: 6 logical name: /dev/sda6 logical name: / capacity: 46GiB configuration: mount.fstype=ext4 mount.options=rw,relatime,errors=remount-ro,user_xattr,barrier=1,data=ordered state=mounted *-cdrom description: DVD-RAM writer product: DVD-RW DVRTD11RS vendor: PIONEER physical id: 1 bus info: scsi@1:0.0.0 logical name: /dev/cdrom logical name: /dev/cdrw logical name: /dev/dvd logical name: /dev/dvdrw logical name: /dev/sr0 version: 1.01 capabilities: removable audio cd-r cd-rw dvd dvd-r dvd-ram configuration: ansiversion=5 status=nodisc *-serial UNCLAIMED description: SMBus product: 6 Series/C200 Series Chipset Family SMBus Controller vendor: Intel Corporation physical id: 1f.3 bus info: pci@0000:00:1f.3 version: 04 width: 64 bits clock: 33MHz configuration: latency=0 resources: memory:d1a06000-d1a060ff ioport:3040(size=32) *-power UNCLAIMED description: OEM_Define1 product: OEM_Define5 vendor: OEM_Define2 physical id: 1 version: OEM_Define6 serial: OEM_Define3 capacity: 75mWh *-battery description: Lithium Ion Battery product: CRB Battery 0 vendor: -Virtual Battery 0- physical id: 2 version: 10/12/2007 serial: Battery 0 slot: Fake

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  • Error when I try to installth desktop integration features for Openoffice

    - by PENG TENG
    peng@peng-ThinkPad-SL410:~$ cd '/home/peng/Downloads/en-US/DEBS/desktop-integration' peng@peng-ThinkPad-SL410:~/Downloads/en-US/DEBS/desktop-integration$ sudo dpkg -i *.deb (Reading database ... 357248 files and directories currently installed.) Unpacking openoffice.org-debian-menus (from openoffice.org3.4-debian-menus_3.4-9593_all.deb) ... dpkg: error processing openoffice.org3.4-debian-menus_3.4-9593_all.deb (--install): trying to overwrite '/usr/bin/soffice', which is also in package libreoffice-common 1:3.6.2~rc2-0ubuntu3 /usr/bin/gtk-update-icon-cache gtk-update-icon-cache: Cache file created successfully. /usr/bin/gtk-update-icon-cache gtk-update-icon-cache: Cache file created successfully. Processing triggers for menu ... Processing triggers for hicolor-icon-theme ... Processing triggers for gnome-icon-theme ... Processing triggers for shared-mime-info ... Unknown media type in type 'all/all' Unknown media type in type 'all/allfiles' Unknown media type in type 'uri/mms' Unknown media type in type 'uri/mmst' Unknown media type in type 'uri/mmsu' Unknown media type in type 'uri/pnm' Unknown media type in type 'uri/rtspt' Unknown media type in type 'uri/rtspu' Processing triggers for bamfdaemon ... Rebuilding /usr/share/applications/bamf.index... Processing triggers for desktop-file-utils ... Processing triggers for gnome-menus ... Errors were encountered while processing: openoffice.org3.4-debian-menus_3.4-9593_all.deb Can anyone solve the problem?

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  • Inside the DLR – Invoking methods

    - by Simon Cooper
    So, we’ve looked at how a dynamic call is represented in a compiled assembly, and how the dynamic lookup is performed at runtime. The last piece of the puzzle is how the resolved method gets invoked, and that is the subject of this post. Invoking methods As discussed in my previous posts, doing a full lookup and bind at runtime each and every single time the callsite gets invoked would be far too slow to be usable. The results obtained from the callsite binder must to be cached, along with a series of conditions to determine whether the cached result can be reused. So, firstly, how are the conditions represented? These conditions can be anything; they are determined entirely by the semantics of the language the binder is representing. The binder has to be able to return arbitary code that is then executed to determine whether the conditions apply or not. Fortunately, .NET 4 has a neat way of representing arbitary code that can be easily combined with other code – expression trees. All the callsite binder has to return is an expression (called a ‘restriction’) that evaluates to a boolean, returning true when the restriction passes (indicating the corresponding method invocation can be used) and false when it does’t. If the bind result is also represented in an expression tree, these can be combined easily like so: if ([restriction is true]) { [invoke cached method] } Take my example from my previous post: public class ClassA { public static void TestDynamic() { CallDynamic(new ClassA(), 10); CallDynamic(new ClassA(), "foo"); } public static void CallDynamic(dynamic d, object o) { d.Method(o); } public void Method(int i) {} public void Method(string s) {} } When the Method(int) method is first bound, along with an expression representing the result of the bind lookup, the C# binder will return the restrictions under which that bind can be reused. In this case, it can be reused if the types of the parameters are the same: if (thisArg.GetType() == typeof(ClassA) && arg1.GetType() == typeof(int)) { thisClassA.Method(i); } Caching callsite results So, now, it’s up to the callsite to link these expressions returned from the binder together in such a way that it can determine which one from the many it has cached it should use. This caching logic is all located in the System.Dynamic.UpdateDelegates class. It’ll help if you’ve got this type open in a decompiler to have a look yourself. For each callsite, there are 3 layers of caching involved: The last method invoked on the callsite. All methods that have ever been invoked on the callsite. All methods that have ever been invoked on any callsite of the same type. We’ll cover each of these layers in order Level 1 cache: the last method called on the callsite When a CallSite<T> object is first instantiated, the Target delegate field (containing the delegate that is called when the callsite is invoked) is set to one of the UpdateAndExecute generic methods in UpdateDelegates, corresponding to the number of parameters to the callsite, and the existance of any return value. These methods contain most of the caching, invoke, and binding logic for the callsite. The first time this method is invoked, the UpdateAndExecute method finds there aren’t any entries in the caches to reuse, and invokes the binder to resolve a new method. Once the callsite has the result from the binder, along with any restrictions, it stitches some extra expressions in, and replaces the Target field in the callsite with a compiled expression tree similar to this (in this example I’m assuming there’s no return value): if ([restriction is true]) { [invoke cached method] return; } if (callSite._match) { _match = false; return; } else { UpdateAndExecute(callSite, arg0, arg1, ...); } Woah. What’s going on here? Well, this resulting expression tree is actually the first level of caching. The Target field in the callsite, which contains the delegate to call when the callsite is invoked, is set to the above code compiled from the expression tree into IL, and then into native code by the JIT. This code checks whether the restrictions of the last method that was invoked on the callsite (the ‘primary’ method) match, and if so, executes that method straight away. This means that, the next time the callsite is invoked, the first code that executes is the restriction check, executing as native code! This makes this restriction check on the primary cached delegate very fast. But what if the restrictions don’t match? In that case, the second part of the stitched expression tree is executed. What this section should be doing is calling back into the UpdateAndExecute method again to resolve a new method. But it’s slightly more complicated than that. To understand why, we need to understand the second and third level caches. Level 2 cache: all methods that have ever been invoked on the callsite When a binder has returned the result of a lookup, as well as updating the Target field with a compiled expression tree, stitched together as above, the callsite puts the same compiled expression tree in an internal list of delegates, called the rules list. This list acts as the level 2 cache. Why use the same delegate? Stitching together expression trees is an expensive operation. You don’t want to do it every time the callsite is invoked. Ideally, you would create one expression tree from the binder’s result, compile it, and then use the resulting delegate everywhere in the callsite. But, if the same delegate is used to invoke the callsite in the first place, and in the caches, that means each delegate needs two modes of operation. An ‘invoke’ mode, for when the delegate is set as the value of the Target field, and a ‘match’ mode, used when UpdateAndExecute is searching for a method in the callsite’s cache. Only in the invoke mode would the delegate call back into UpdateAndExecute. In match mode, it would simply return without doing anything. This mode is controlled by the _match field in CallSite<T>. The first time the callsite is invoked, _match is false, and so the Target delegate is called in invoke mode. Then, if the initial restriction check fails, the Target delegate calls back into UpdateAndExecute. This method sets _match to true, then calls all the cached delegates in the rules list in match mode to try and find one that passes its restrictions, and invokes it. However, there needs to be some way for each cached delegate to inform UpdateAndExecute whether it passed its restrictions or not. To do this, as you can see above, it simply re-uses _match, and sets it to false if it did not pass the restrictions. This allows the code within each UpdateAndExecute method to check for cache matches like so: foreach (T cachedDelegate in Rules) { callSite._match = true; cachedDelegate(); // sets _match to false if restrictions do not pass if (callSite._match) { // passed restrictions, and the cached method was invoked // set this delegate as the primary target to invoke next time callSite.Target = cachedDelegate; return; } // no luck, try the next one... } Level 3 cache: all methods that have ever been invoked on any callsite with the same signature The reason for this cache should be clear – if a method has been invoked through a callsite in one place, then it is likely to be invoked on other callsites in the codebase with the same signature. Rather than living in the callsite, the ‘global’ cache for callsite delegates lives in the CallSiteBinder class, in the Cache field. This is a dictionary, typed on the callsite delegate signature, providing a RuleCache<T> instance for each delegate signature. This is accessed in the same way as the level 2 callsite cache, by the UpdateAndExecute methods. When a method is matched in the global cache, it is copied into the callsite and Target cache before being executed. Putting it all together So, how does this all fit together? Like so (I’ve omitted some implementation & performance details): That, in essence, is how the DLR performs its dynamic calls nearly as fast as statically compiled IL code. Extensive use of expression trees, compiled to IL and then into native code. Multiple levels of caching, the first of which executes immediately when the dynamic callsite is invoked. And a clever re-use of compiled expression trees that can be used in completely different contexts without being recompiled. All in all, a very fast and very clever reflection caching mechanism.

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  • How to cache authentication in Linux using PAM/Kerberos authentication (for CVS)?

    - by Calonthar
    We have several Linux servers that authenticate Linux user passwords on our Windows Active Directory Server using PAM and Kerberos 5. The Linux distro we use is CentOS 6. On one system, we have several Version Control Systems like CVS and Subversion, both of which authenticate users throug PAM, such that users can use their normal Unix resp. Windows AD accounts. Since we started using Kerberos for password authentication, we experienced that CVS on a client machine is often much slower in establishing a connection. CVS authenticates the user on every request (eg. cvs diff, log, update...). Is is possible to cache the credentials that kerberos uses, sucht that is does not need to ask the Windows AD server every time a user executes a cvs action? Our PAM config /etc/pam.d/system-auth looks like the following: auth required pam_env.so auth sufficient pam_unix.so nullok try_first_pass auth requisite pam_succeed_if.so uid >= 500 quiet auth sufficient pam_krb5.so use_first_pass auth required pam_deny.so account required pam_unix.so broken_shadow account sufficient pam_succeed_if.so uid < 500 quiet account [default=bad success=ok user_unknown=ignore] pam_krb5.so account required pam_permit.so password requisite pam_cracklib.so try_first_pass retry=3 password sufficient pam_unix.so md5 shadow nullok try_first_pass use_authtok password sufficient pam_krb5.so use_authtok password required pam_deny.so session optional pam_keyinit.so revoke session required pam_limits.so session [success=1 default=ignore] pam_succeed_if.so service in crond quiet use_uid session required pam_unix.so session optional pam_krb5.so

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  • Strange issue ! Local network cache of PHP and Apache2 on Win Server 2008 R2

    - by Ahmed Benlahsen
    Software configuration : I have a new Server with windows server 2008 R2 installed via VMWare. I have installed Apache2.2, PHP5.2 and MySQL5.5 as separated packages. Issue : On my first installation of my application all works great. When I updated some JS and CSS files then I access to my application again from a PC on local network I get the old JS and CSS versions! But when I access to the same application on local server I got the latest versions of those files! Link of my application on local server is : http://localhost/BADIL Link of my application from local network is : http://LOCAL_SERVER_IP/BADIL I never had this kind of issue! I think that there are some cache but I don't know where! Maybe on Win Server 2008 R2 or on VMWare ! The question is : Why when I access to my application on the server all works fine, but when I access to the same application from a local network I have the old version of JS and CSS files?? Any one can help me please?! Regards.

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