Search Results

Search found 13341 results on 534 pages for 'obiee performance tuning'.

Page 92/534 | < Previous Page | 88 89 90 91 92 93 94 95 96 97 98 99  | Next Page >

  • Hibernate 3.5.0 causes extreme performance problems

    - by user303396
    I've recently updated from hibernate 3.3.1.GA to hibernate 3.5.0 and I'm having a lot of performance issues. As a test, I added around 8000 entities to my DB (which in turn cause other entities to be saved). These entities are saved in batches of 20 so that the transactions aren't too large for performance reasons. When using hibernate 3.3.1.GA all 8000 entities get saved in about 3 minutes. When using hibernate 3.5.0 it starts out slower than with hibernate 3.3.1. But it gets slower and slower. At around 4,000 entities, it sometimes takes 5 minutes just to save a batch of 20. If I then go to a mysql console and manually type in an insert statement from the mysql general query log, half of them run perfect in 0.00 seconds. And half of them take a long time (maybe 40 seconds) or timeout with "ERROR 1205 (HY000): Lock wait timeout exceeded; try restarting transaction" from MySQL. Has something changed in hibernate's transaction management in version 3.5.0 that I should be aware of? The ONLY thing I changed to experience these unusable performance issues is replace the following hibernate 3.3.1.GA jar files: com.springsource.org.hibernate-3.3.1.GA.jar, com.springsource.org.hibernate.annotations-3.4.0.GA.jar, com.springsource.org.hibernate.annotations.common-3.3.0.ga.jar, com.springsource.javassist-3.3.0.ga.jar with the new hibernate 3.5.0 release hibernate3.jar and javassist-3.9.0.GA.jar. Thanks.

    Read the article

  • Static Vs Non-Static Method Performance C#

    - by dotnetguts
    Hello All, I have few global methods declared in public class in my asp.net web application. I have habbit of declaring all global methods in public class in following format public static string MethodName(parameters) { } I want to know how it would impact on performance point of view? 1) Which one is Better? Static Method or Non-Static Method? 2) Reason why it is better? Following link shows Non-Static methods are good because, static methods are using locks to be Thread-safe. The always do internally a Monitor.Enter() and Monitor.exit() to ensure Thread-safety. http://bytes.com/topic/c-sharp/answers/231701-static-vs-non-static-function-performance And Following link shows Static Methods are good static methods are normally faster to invoke on the call stack than instance methods. There are several reasons for this in the C# programming language. Instance methods actually use the 'this' instance pointer as the first parameter, so an instance method will always have that overhead. Instance methods are also implemented with the callvirt instruction in the intermediate language, which imposes a slight overhead. Please note that changing your methods to static methods is unlikely to help much on ambitious performance goals, but it can help a tiny bit and possibly lead to further reductions. http://dotnetperls.com/static-method I am little confuse which one to use? Thanks

    Read the article

  • MS SQL - High performance data inserting with stored procedures

    - by Marks
    Hi. Im searching for a very high performant possibility to insert data into a MS SQL database. The data is a (relatively big) construct of objects with relations. For security reasons i want to use stored procedures instead of direct table access. Lets say i have a structure like this: Document MetaData User Device Content ContentItem[0] SubItem[0] SubItem[1] SubItem[2] ContentItem[1] ... ContentItem[2] ... Right now I think of creating one big query, doing somehting like this (Just pseudo-code): EXEC @DeviceID = CreateDevice ...; EXEC @UserID = CreateUser ...; EXEC @DocID = CreateDocument @DeviceID, @UserID, ...; EXEC @ItemID = CreateItem @DocID, ... EXEC CreateSubItem @ItemID, ... EXEC CreateSubItem @ItemID, ... EXEC CreateSubItem @ItemID, ... ... But is this the best solution for performance? If not, what would be better? Split it into more querys? Give all Data to one big stored procedure to reduce size of query? Any other performance clue? I also thought of giving multiple items to one stored procedure, but i dont think its possible to give a non static amount of items to a stored procedure. Since 'INSERT INTO A VALUES (B,C),(C,D),(E,F) is more performant than 3 single inserts i thought i could get some performance here. Thanks for any hints, Marks

    Read the article

  • Administer, manage, monitor, and fine tune the performance of your Oracle SOA Suite 11g Service Infrastructure and SOA composite applications.

    - by JuergenKress
    Key Features of the book If you are an Oracle SOA suite administrator, then this book is your bible. It gives you everything you need to know about all your tasks and help you to apply what you learn in your everyday life right from the first chapter. The book walks through promoting code across environments, performance tuning the service infrastructure, monitoring the environment, configuring security policies, managing the dehydration store, backing and restoring environments and so on. Packed with real-world examples from authors' own experiences, this books offers a unique insight into Oracle SOA Suite Administration. Detailed description The book begins with an introduction of SOA and quickly moves on to management of SOA composite applications. Readers will learn how to manage composite applications, their deployments and lifecycles. Equipped with this knowledge, readers will be introduced to monitoring and performance tuning SOA Suite, monitoring instances, messages, and composite applications, managing faults and exceptions, configuring audit levels of composite applications to include end-to-end monitoring through the use of extended logging as well as administering and configuring all SOA Suite components. A very important aspect of administration is tuning and optimizing the infrastructure for performance and book offers real work recommendations to monitor and performance tune service engines, the underlying WebLogic server, threads and timeouts, files systems, and composite applications. It also covers detailed administration of individual service components, configuring the infrastructure MBeans using both Oracle Enterprise Manager Fusion Middleware Control and WLST based scripts, migrating worklist preferences and BAM data across environments, setting up Email, LDAP and custom XPath. An administrator is always trusted with troubleshooting and root causing problems in the infrastructure and this book will help you through the troubleshooting approaches as how to identify faults and exception through extended logging and thread dumps and find solutions to common startup problems and deployment issues. The advanced contents of this book explains OWSM security framework and how to secure components deployed to the infrastructure along with the details of all groundwork needed to ready the environment. Last few chapters help you to understand and deal with managing the metadata services repository and dehydration store, backup and recovery and concluding with advanced topics such as silent/scripted installations, cloning, upgrading, patching and high availability installations. Packed with real-world examples, and tips straight from the trench; this book offers insights into SOA Suite administration that you will not find elsewhere. Part of our writing style in this book draws heavily on the philosophy of reuse and as such the book provide an ample of executable SQL queries and WLST scripts that administrators can reuse and extend to perform most of the administration tasks such as monitoring instances, processing times, instance states and perform automatic deployments, tuning, migration, and installation. These scripts are spread over each of the chapters in the book and can also be downloaded from here. The book is available in different formats at the following websites: Paperback and eBook versions & Kindle version. It is available for order and signed copies are available through our web site. SOA & BPM Partner Community For regular information on Oracle SOA Suite become a member in the SOA & BPM Partner Community for registration please visit  www.oracle.com/goto/emea/soa (OPN account required) If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Mix Forum Technorati Tags: SOA book,SOA Suite Adminsitration,SOA Community,Oracle SOA,Oracle BPM,Community,OPN,Jürgen Kress

    Read the article

  • Slow NFS and GFS2 performance

    - by Tiago
    Recently I've designed and configured a 4 node cluster for a webapp that does lots of file handling. The cluster have been broken down into 2 main roles, webserver and storage. Each role is replicated to a second server using drbd in active/passive mode. The webserver does a NFS mount of the data directory of the storage server and the latter also has a webserver running to serve files to browser clients. In the storage servers I've created a GFS2 FS to hold the data which is wired to drbd. I've chose GFS2 mainly because the announced performance and also because the volume size which has to be pretty high. Since we entered production I've been facing two problems that I think are deeply connected. First of all, the NFS mount on the webservers keeps hanging for a minute or so and then resumes normal operations. By analyzing the logs I've found out that NFS stops answering for a while and outputs the following log lines: Oct 15 18:15:42 <server hostname> kernel: nfs: server active.storage.vlan not responding, still trying Oct 15 18:15:44 <server hostname> kernel: nfs: server active.storage.vlan not responding, still trying Oct 15 18:15:46 <server hostname> kernel: nfs: server active.storage.vlan not responding, still trying Oct 15 18:15:47 <server hostname> kernel: nfs: server active.storage.vlan not responding, still trying Oct 15 18:15:47 <server hostname> kernel: nfs: server active.storage.vlan not responding, still trying Oct 15 18:15:47 <server hostname> kernel: nfs: server active.storage.vlan not responding, still trying Oct 15 18:15:48 <server hostname> kernel: nfs: server active.storage.vlan not responding, still trying Oct 15 18:15:48 <server hostname> kernel: nfs: server active.storage.vlan not responding, still trying Oct 15 18:15:51 <server hostname> kernel: nfs: server active.storage.vlan not responding, still trying Oct 15 18:15:52 <server hostname> kernel: nfs: server active.storage.vlan not responding, still trying Oct 15 18:15:52 <server hostname> kernel: nfs: server active.storage.vlan not responding, still trying Oct 15 18:15:55 <server hostname> kernel: nfs: server active.storage.vlan not responding, still trying Oct 15 18:15:55 <server hostname> kernel: nfs: server active.storage.vlan not responding, still trying Oct 15 18:15:58 <server hostname> kernel: nfs: server active.storage.vlan OK Oct 15 18:15:59 <server hostname> kernel: nfs: server active.storage.vlan OK Oct 15 18:15:59 <server hostname> kernel: nfs: server active.storage.vlan OK Oct 15 18:15:59 <server hostname> kernel: nfs: server active.storage.vlan OK Oct 15 18:15:59 <server hostname> kernel: nfs: server active.storage.vlan OK Oct 15 18:15:59 <server hostname> kernel: nfs: server active.storage.vlan OK Oct 15 18:15:59 <server hostname> kernel: nfs: server active.storage.vlan OK Oct 15 18:15:59 <server hostname> kernel: nfs: server active.storage.vlan OK Oct 15 18:15:59 <server hostname> kernel: nfs: server active.storage.vlan OK Oct 15 18:15:59 <server hostname> kernel: nfs: server active.storage.vlan OK Oct 15 18:15:59 <server hostname> kernel: nfs: server active.storage.vlan OK Oct 15 18:15:59 <server hostname> kernel: nfs: server active.storage.vlan OK Oct 15 18:15:59 <server hostname> kernel: nfs: server active.storage.vlan OK In this case, the hang lasted for 16 seconds but sometimes it takes 1 or 2 minutes to resume normal operations. My first guess was this was happening due to heavy load of the NFS mount and that by increasing RPCNFSDCOUNT to a higher value, this would become stable. I've increased it several times and apparently, after a while, the logs started appearing less times. The value is now on 32. After further investigating the issue, I've came across a different hang, despite the NFS messages still appear in the logs. Sometimes, the GFS2 FS simply hangs which causes both the NFS and the storage webserver to serve files. Both stay hang for a while and then they resume normal operations. This hangs leaves no trace on client side (also leaves no NFS ... not responding messages) and, on the storage side, the log system appears to be empty, even though the rsyslogd is running. The nodes connect themselves through a 10Gbps non-dedicated connection but I don't think this is an issue because the GFS2 hang is confirmed but connecting directly to the active storage server. I've been trying to solve this for a while now and I've tried different NFS configuration options, before I've found out the GFS2 FS is also hanging. The NFS mount is exported as such: /srv/data/ <ip_address>(rw,async,no_root_squash,no_all_squash,fsid=25) And the NFS client mounts with: mount -o "async,hard,intr,wsize=8192,rsize=8192" active.storage.vlan:/srv/data /srv/data After some tests, these were the configurations that yielded more performance to the cluster. I am desperate to find a solution for this as the cluster is already in production mode and I need to fix this so that this hangs won't happen in the future and I don't really know for sure what and how I should be benchmarking. What I can tell is that this is happening due to heavy loads as I have tested the cluster earlier and this problems weren't happening at all. Please tell me if you need me to provide configuration details of the cluster, and which do you want me to post. As last resort I can migrate the files to a different FS but I need some solid pointers on whether this will solve this problems as the volume size is extremely large at this point. The servers are being hosted by a third-party enterprise and I don't have physical access to them. Best regards. EDIT 1: The servers are physical servers and their specs are: Webservers: Intel Bi Xeon E5606 2x4 2.13GHz 24GB DDR3 Intel SSD 320 2 x 120GB Raid 1 Storage: Intel i5 3550 3.3GHz 16GB DDR3 12 x 2TB SATA Initially there was a VRack setup between the servers but we've upgraded one of the storage servers to have more RAM and it wasn't inside the VRack. They connect through a shared 10Gbps connection between them. Please note that it is the same connection that is used for public access. They use a single IP (using IP Failover) to connect between them and to allow for a graceful failover. NFS is therefore over a public connection and not under any private network (it was before the upgrade, were the problem still existed). The firewall was configured and tested thoroughly but I disabled it for a while to see if the problem still occurred, and it did. From my knowledge the hosting provider isn't blocking or limiting the connection between either the servers and the public domain (at least under a given bandwidth consumption threshold that hasn't been reached yet). Hope this helps figuring out the problem. EDIT 2: Relevant software versions: CentOS 2.6.32-279.9.1.el6.x86_64 nfs-utils-1.2.3-26.el6.x86_64 nfs-utils-lib-1.1.5-4.el6.x86_64 gfs2-utils-3.0.12.1-32.el6_3.1.x86_64 kmod-drbd84-8.4.2-1.el6_3.elrepo.x86_64 drbd84-utils-8.4.2-1.el6.elrepo.x86_64 DRBD configuration on storage servers: #/etc/drbd.d/storage.res resource storage { protocol C; on <server1 fqdn> { device /dev/drbd0; disk /dev/vg_storage/LV_replicated; address <server1 ip>:7788; meta-disk internal; } on <server2 fqdn> { device /dev/drbd0; disk /dev/vg_storage/LV_replicated; address <server2 ip>:7788; meta-disk internal; } } NFS Configuration in storage servers: #/etc/sysconfig/nfs RPCNFSDCOUNT=32 STATD_PORT=10002 STATD_OUTGOING_PORT=10003 MOUNTD_PORT=10004 RQUOTAD_PORT=10005 LOCKD_UDPPORT=30001 LOCKD_TCPPORT=30001 (can there be any conflict in using the same port for both LOCKD_UDPPORT and LOCKD_TCPPORT?) GFS2 configuration: # gfs2_tool gettune <mountpoint> incore_log_blocks = 1024 log_flush_secs = 60 quota_warn_period = 10 quota_quantum = 60 max_readahead = 262144 complain_secs = 10 statfs_slow = 0 quota_simul_sync = 64 statfs_quantum = 30 quota_scale = 1.0000 (1, 1) new_files_jdata = 0 Storage network environment: eth0 Link encap:Ethernet HWaddr <mac address> inet addr:<ip address> Bcast:<bcast address> Mask:<ip mask> inet6 addr: <ip address> Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:957025127 errors:0 dropped:0 overruns:0 frame:0 TX packets:1473338731 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:2630984979622 (2.3 TiB) TX bytes:1648430431523 (1.4 TiB) eth0:0 Link encap:Ethernet HWaddr <mac address> inet addr:<ip failover address> Bcast:<bcast address> Mask:<ip mask> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 The IP addresses are statically assigned with the given network configurations: DEVICE="eth0" BOOTPROTO="static" HWADDR=<mac address> ONBOOT="yes" TYPE="Ethernet" IPADDR=<ip address> NETMASK=<net mask> and DEVICE="eth0:0" BOOTPROTO="static" HWADDR=<mac address> IPADDR=<ip failover> NETMASK=<net mask> ONBOOT="yes" BROADCAST=<bcast address> Hosts file to allow for a graceful NFS failover in conjunction with NFS option fsid=25 set on both storage servers: #/etc/hosts <storage ip failover address> active.storage.vlan <webserver ip failover address> active.service.vlan As you can see, packet errors are down to 0. I've also ran ping for a long time without any packet loss. MTU size is the normal 1500. As there is no VLan by now, this is the MTU used to communicate between servers. The webservers' network environment is similar. One thing I forgot to mention is that the storage servers handle ~200GB of new files each day through the NFS connection, which is a key point for me to think this is some kind of heavy load problem with either NFS or GFS2. If you need further configuration details please tell me. EDIT 3: Earlier today we had a major filesystem crash on the storage server. I couldn't get the details of the crash right away because the server stop responding. After the reboot, I noticed the filesystem was extremely slow, and I was not being able to serve a single file through either NFS or httpd, perhaps due to cache warming or so. Nevertheless, I've been monitoring the server closely and the following error came up in dmesg. The source of the problem is clearly GFS, which is waiting for a lock and ends up starving after a while. INFO: task nfsd:3029 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. nfsd D 0000000000000000 0 3029 2 0x00000080 ffff8803814f79e0 0000000000000046 0000000000000000 ffffffff8109213f ffff880434c5e148 ffff880624508d88 ffff8803814f7960 ffffffffa037253f ffff8803815c1098 ffff8803814f7fd8 000000000000fb88 ffff8803815c1098 Call Trace: [<ffffffff8109213f>] ? wake_up_bit+0x2f/0x40 [<ffffffffa037253f>] ? gfs2_holder_wake+0x1f/0x30 [gfs2] [<ffffffff814ff42e>] __mutex_lock_slowpath+0x13e/0x180 [<ffffffff814ff2cb>] mutex_lock+0x2b/0x50 [<ffffffffa0379f21>] gfs2_log_reserve+0x51/0x190 [gfs2] [<ffffffffa0390da2>] gfs2_trans_begin+0x112/0x1d0 [gfs2] [<ffffffffa0369b05>] ? gfs2_dir_check+0x35/0xe0 [gfs2] [<ffffffffa0377943>] gfs2_createi+0x1a3/0xaa0 [gfs2] [<ffffffff8121aab1>] ? avc_has_perm+0x71/0x90 [<ffffffffa0383d1e>] gfs2_create+0x7e/0x1a0 [gfs2] [<ffffffffa037783f>] ? gfs2_createi+0x9f/0xaa0 [gfs2] [<ffffffff81188cf4>] vfs_create+0xb4/0xe0 [<ffffffffa04217d6>] nfsd_create_v3+0x366/0x4c0 [nfsd] [<ffffffffa0429703>] nfsd3_proc_create+0x123/0x1b0 [nfsd] [<ffffffffa041a43e>] nfsd_dispatch+0xfe/0x240 [nfsd] [<ffffffffa025a5d4>] svc_process_common+0x344/0x640 [sunrpc] [<ffffffff810602a0>] ? default_wake_function+0x0/0x20 [<ffffffffa025ac10>] svc_process+0x110/0x160 [sunrpc] [<ffffffffa041ab62>] nfsd+0xc2/0x160 [nfsd] [<ffffffffa041aaa0>] ? nfsd+0x0/0x160 [nfsd] [<ffffffff81091de6>] kthread+0x96/0xa0 [<ffffffff8100c14a>] child_rip+0xa/0x20 [<ffffffff81091d50>] ? kthread+0x0/0xa0 [<ffffffff8100c140>] ? child_rip+0x0/0x20

    Read the article

  • TaskFactory.StartNew versus ThreadPool.QueueUserWorkItem

    - by Dan Tao
    Apparently the TaskFactory.StartNew method in .NET 4.0 is intended as a replacement for ThreadPool.QueueUserWorkItem (according to this post, anyway). My question is simple: does anyone know why? Does TaskFactory.StartNew have better performance? Does it use less memory? Or is it mainly for the additional functionality provided by the Task class? In the latter case, does StartNew possibly have worse performance than QueueUserWorkItem? It seems to me that StartNew would actually potentially use more memory than QueueUserWorkItem, since it returns a Task object with every call and I would expect that to result in more memory allocation. In any case, I'm interested to know which is more appropriate for a high-performance scenario.

    Read the article

  • Is using ReaderWriterLockSlim a bad idea for long lived objects?

    - by uriDium
    I am trying to track down the reason that an application has periods of bad performance. I think that I have linked the bad performance to the points where Garbage Collection is run for Gen 2. I get a profiling tool (CLR Profiler) and was quite surprised by the results. In my test I was spawning and processing millions of objects. However the biggest hog of the Gen 2 space comes from something Called Threading.ReaderWriterCount which comes from System.Threading.ReaderWriterLockSlim::InitializeThreadCounts. I know nothing about the inner workings of ReaderWriterLockSlim but from what I am getting from the reports it is okay to have 1 or 2 Locks for longer lived objects but try and use other locks if you are going to have many smaller objects. Does anyone have any comments or experience with ReaderWriterLockSlim and/or what to look for if it seems that GC is killing application performance?

    Read the article

  • how to store dynamically generated pages in html?

    - by Dharmik Bhandari
    I'm working on ASP.net MVC3 Web application that is facing scalability issue. For improving performance I want to store dynamically generated pages in html and serve them from generated html directly rather then querying database for each page request. I'm sure this will dramatically increase performance. Can any one share any hint / example / tutorial on how to do it? And what are challenges? I would also like to know how others are handling performance issue for large e-commerce sites with at-least thousand categories and 200k products with at least 200-500 concurrent visitors? What are the best approaches? Thanks in advance.

    Read the article

  • Would using a MemoryMappedFile for IPC across AppDomains be faster than WCF/named pipes?

    - by Morten Mertner
    Context: I am loading and executing untrusted code in a separate AppDomain and am currently communicating between the two using WCF (using named pipes as the underlying transport). I am exchanging relatively simple object graphs using a reasonably coarse-grained API, but would like to use a more fine-grained API if it does not cost me performance-wise. I've noticed that 4.0 adds a MemoryMappedFile class (which doesn't need a physical file, so could be entirely memory based). What kind of performance gains could I expect to see (if any) by using this new class? I know that it would take some "infrastructure code" to get the request/response behavior of WCF, but for now I'm only interested in the performance difference.

    Read the article

  • Do bit operations cause programs to run slower?

    - by flashnik
    I'm dealing with a problem which needs to work with a lot of data. Currently its values are represented as an unsigned int. I know that real values do not exceed a limit of 1000. Questions I can use unsigned short to store it. An upside to this is that it'll use less storage space to store the value. Will performance suffer? If I decided to store data as short but all the calling functions use int, it's recognized that I need to convert between these datatypes when storing or extracting values. Will performance suffer? Will the loss in performance be dramatic? If I decided to not use short but just 10 bits packed into an array of unsigned int. What will happen in this case comparing with previous ones?

    Read the article

  • SQL Server 2005 - Understanding ouput of DBCC SHOWCONTIG

    - by user169743
    I'm seeing some slow performance on a SQL Server 2005 database. I've been doing some research regarding SQL Server performance but I'm having difficulty fully understanding the output of SHOWCONTIG and would be very grateful if someone could have a look and offer some suggestions to improve performance. TABLE level scan performed. Pages Scanned................................: 19348 Extents Scanned..............................: 2427 Extent Switches..............................: 3829 Avg. Pages per Extent........................: 8.0 Scan Density [Best Count:Actual Count].......: 63.16% [2419:3830] Logical Scan Fragmentation ..................: 8.40% Extent Scan Fragmentation ...................: 35.15% Avg. Bytes Free per Page.....................: 938.1 Avg. Page Density (full).....................: 88.41%

    Read the article

  • MS SQL 2005 - Understanding ouput of DBCC SHOWCONTIG

    - by user169743
    I'm seeing some slow performance on a MS SQL 2005 database. I've been doing some research regarding MS SQL performance but I'm having difficulty fully understanding the output of SHOWCONTIG and would be very grateful if someone could have a look and offer some suggestions to improve performance. TABLE level scan performed. Pages Scanned................................: 19348 Extents Scanned..............................: 2427 Extent Switches..............................: 3829 Avg. Pages per Extent........................: 8.0 Scan Density [Best Count:Actual Count].......: 63.16% [2419:3830] Logical Scan Fragmentation ..................: 8.40% Extent Scan Fragmentation ...................: 35.15% Avg. Bytes Free per Page.....................: 938.1 Avg. Page Density (full).....................: 88.41%

    Read the article

  • Common causes of slow performing jQuery and how to optimize the code?

    - by Polaris878
    Hello, This might be a bit of a vague or general question, but I figure it might be able to serve as a good resource for other jQuery-ers. I'm interested in common causes of slow running jQuery and how to optimize these cases. We have a good amount of jQuery/JavaScript performing actions on our page... and performance can really suffer with a large number off elements. What are some obvious performance pitfalls you know of with jQuery? What are some general optimizations a jQuery-er can do to squeeze every last bit of performance out of his/her scripts? One example: a developer may use a selector to access an element that is slower than some other way. Thanks

    Read the article

  • C++0x optimizing compiler quality

    - by aaa
    hello. I do some heavy numbercrunching and for me floating-point performance is very important. I like performance of Intel compiler very much and quite content with quality of assembly it produces. I am thinking at some point to try C++0x mainly for sugar parts, like auto, initializer list, etc, but also lambdas. at this point I use those features in regular C++ by the means of boost. How good of assembly code do compilers C++0x generate? specifically Intel and gcc compilers. Do they produce SSE code? is performance comparable to C++? are there any benchmarks? My Google search did not reveal much. Thank you.

    Read the article

  • Writing at the end of file

    - by user342534
    Hi, I'm working on a system that requires high file I/O performance (with C#). Basically, I'm filling up large files (~100MB) from the start of the file until the end of the file. Every ~5 seconds I'm adding ~5MB to the file (sequentially from the start of the file), on every bulk I'm flushing the stream. Every few minutes I need to update a structure which I write at the end of the file (some kind of metadata). When flushing each one of the bulks I have no performance issue. However, when updating the metadata at the end of the file I get really low performance. My guess is that when creating the file (which also should be done extra fast), the file doesn't really allocates the entire 100MB on the disk and when I flush the metadata it must allocates all space until the end of file. Guys/Girls, any Idea how I can overcome this problem? Thanks a lot!

    Read the article

  • Why would SQL be very slow when doing updates?

    - by ooo
    Suddenly doing updates into a few tables have gotten 10 times slower than they used to be. What are some good recommendations to determine root cause and optimization? Could it be that indexing certain columns are causing updates to be slow? Any other recommendations? I guess more important than guesses would be help on the process of identifying the root cause or metrics around performance. Is there anything in Fluent NHibernate that you can use to help identify the root cause of performance issues?

    Read the article

  • USB 3 vs. eSATA

    - by Robert Nickens
    Will the full speed advantages of the future USB 3.0 be negated by the fact the most HD being mass produced are SATA 3? If so, what would you suggest a person do? For performance reasons go with eSATA or 1394 for external HDs. Why spend the money on USB 3.0 next year,even if the prices come down quickly. Given that SATA 6 is not here and may be a while.

    Read the article

  • "Task Manager" addon for Firefox?

    - by eidylon
    Hello all... I'm wondering if there is an addon for Firefox that would basically replicate the performance monitoring of Task Manager in Windows - seeing memory and cpu used - but for all the tabs in your current Firefox session. I want to be able to see which tabs are taking up the most memory or hitting hardest on the CPU. Thanks in advance!

    Read the article

  • ASPNET WMI class not available

    - by Nexus
    I need to extract the ASPNET\Requests Queued performance counter from some IIS servers via WMI. The WMI class for this sort of thing appears to be contained in Win32_PerfFormattedData_ASPNET_ASPNET. I've queried all available classes in root\cimv2 on my Win 2003/IIS6 servers, and it's not listed. It is, however, available on an unrelated Win2008/IIS7 box (which is interesting but doesn't really help me much) What gives? Why is this WMI class not available on my Windows 2003 servers?

    Read the article

  • IRP_MJ_WRITE latency up to 15 seconds

    - by racitup
    We have written an application that performs small (22kB) writes to multiple files at once (one thread performing asynchronous queued writes to multiple locations on behalf of other threads) on the same local volume (RAID1). 99.9% of the writes are low-latency but occasionally (maybe every minute or two) we get one or two huge latency writes (I have seen 10 seconds and above) without any real explanation. Platform: Win2003 Server with NTFS. Monitoring: Sysinternals Process Monitor (see link below) and our own application logging. We have tried multiple things to try and solve this that have been gleaned from a few websites, e.g.: Making the first part of file names unique to aid 8.3 name generation Writing files to multiple directories Changing Intel Disk Write Caching Windows File/Printer Sharing Minimize memory used Balance Maximize data throughput for file sharing Maximize data throughput for network applications System-Advanced-Performance-Advanced NtfsDisableLastAccessUpdate - use fsutil behavior set disablelastaccess 1 disable 8.3 name generation - use "fsutil behavior set disable8dot3 1" + restart Enable a large size file system cache Disable paging of the kernel code IO Page Lock Limit Turn Off (or On) the Indexing Service But nothing seems to make much difference. There's a whole host of things we haven't tried yet but we wondered if anyone had come across the same problem, a reason and a solution (programmatic or not)? We can reproduce the problem using IOMeter and a simple setup: Start IOMeter and remove all but the first worker thread in 'Topology' using the disconnect button. Select the Worker thread and put a cross in the box next to the disk you want to use in the Disk Targets tab and put '2000000' in Maximum Disk Size (NOTE: must have at least 1GB free space; sector size is 512 bytes) Next create a new access specification and add it to the worker thread: Transfer Request Size = 22kB 100% Sequential Percent of Access Spec = 100% Percent Read/Write = 100% Write Change Results Display Update Frequency to 5 seconds, Test Setup Run Time to 20 seconds and both 'Number of Workers to Spawn Automatically' settings to zero. Select the Worker Thread in the Topology panel and hit the Duplicate Worker button 59 times to create 60 threads with identical settings. Hit the 'Go' button (green flag) and monitor the Results tab. The 'Maximum I/O Response Time (ms)' always hits at least 3500 on our machine. Our machine isn't exactly slow (Xeon 8 core rack server with 4GB and onboard RAID). I'd be interested to see what other people get. We have a feeling it might be something to do with the NTFS filesystem (ours is currently 75% full of fragmented files) and we are going to try a few things around this principle. But it is also related to disk performance since we don't see it on a RAMDisk and it's not as severe on a RAID10 array. Any help is much appreciated. Richard Right-click and select 'Open Link in New Tab': ProcMon Result

    Read the article

  • Why does jmeter not work?

    - by Foolish
    I use jmeter to record requests and then perform a performance test after it records all the requests with proxy server. These requests contain a post form. After that I run the test cases, but I found the post form doesn't work -- it cannot create a record in the website's database automatically. But before that I used Webload and everything was OK. What's the problem? What can I do for this?

    Read the article

  • Any reason not to disable Windows kernel paging?

    - by Nathaniel
    So I'm planning on eventually going to 2 GB (mobo max) RAM from 1 GB, and I want to disable kernel paging once I do, because I've heard it can give a performance boost (and that I believe). Any reason not to do it or any general thoughts about it? Edit: for clarification, this is not disabling general RAM paging. This is disabling having kernel memory paged (or at least parts of it, as Charlls noted).

    Read the article

  • How to correctly partition usb flash drive and which filesystem to choose considering wear leveling?

    - by random1
    Two problems. First one: how to partition the flash drive? I shouldn't need to do this, but I'm no longer sure if my partition is properly aligned since I was forced to delete and create a new partition table after gparted complained when I tried to format the drive from FAT to ext4. The naive answer would be to say "just use default and everything is going to be alright". However if you read the following links you'll know things are not that simple: https://lwn.net/Articles/428584/ and http://linux-howto-guide.blogspot.com/2009/10/increase-usb-flash-drive-write-speed.html Then there is also the issue of cylinders, heads and sectors. Currently I get this: $sfdisk -l -uM /dev/sdd Disk /dev/sdd: 30147 cylinders, 64 heads, 32 sectors/track Warning: The partition table looks like it was made for C/H/S=*/255/63 (instead of 30147/64/32). For this listing I'll assume that geometry. Units = mebibytes of 1048576 bytes, blocks of 1024 bytes, counting from 0 Device Boot Start End MiB #blocks Id System /dev/sdd1 1 30146 30146 30869504 83 Linux $fdisk -l /dev/sdd Disk /dev/sdd: 31.6 GB, 31611420672 bytes 255 heads, 63 sectors/track, 3843 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00010c28 So from my current understanding I should align partitions at 4 MiB (currently it's at 1 MiB). But I still don't know how to set the heads and sectors properly for my device. Second problem: file system. From the benchmarks I saw ext4 provides the best performance, however there is the issue of wear leveling. How can I know that my Transcend JetFlash 700's microcontroller provides for wear leveling? Or will I just be killing my drive faster? I've seen a lot of posts on the web saying don't worry the newer drives already take care of that. But I've never seen a single piece of backed evidence of that and at some point people start mixing SSD with USB flash drives technology. The safe option would be to go for ext2, however a serious of tests that I performed showed horrible performance!!! These values are from a real scenario and not some synthetic test: 42 files: 3,429,415,284 bytes copied to flash drive original fat32: 15.1 MiB/s ext4 after new partition table: 10.2 MiB/s ext2 after new partition table: 1.9 MiB/s Please read the links that I posted above before answering. I would also be interested in answers backed up with some references because a lot is said and re-said but then it lacks facts. Thank you for the help.

    Read the article

  • Android emulator performance on linux

    - by Rado
    I installed the android SDK and eclipse plugin on my laptop, but I was surprised to find out that the emulator eats up 100% of one of my cpu cores. I have exactly the same setup on a desktop machine that does not have this issue. Both computers are running arch linux and both were updated yesterday. Granted, the desktop has better hardware than the laptop, but I was expecting to get closer to 50% cpu usage than 100% on the laptop. Both android virtual devices have the same specs: CPU: ARM Target: Android 2.3.3 - API Level 10 Skin: WVGA800 SD Card: 512M hw.lcd.density: 240 vm.heapSize: 24 hw.ramSize: 256 Laptop host has Intel Core 2 T7200 @ 2GHz cpu with 2Gb RAM. Desktop host has AMD Phenom II X4 940 @ 3GHz cpu with 8Gb RAM. The android emulator uses only 1 core and here are the CPU usage results: Laptop: Cpu0 : 22.8%us, 76.5%sy, 0.0%ni, 0.3%id, 0.0%wa, 0.0%hi, 0.3%si, 0.0%st Cpu1 : 11.2%us, 2.4%sy, 0.0%ni, 86.4%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 2055484k total, 1860304k used, 195180k free, 5276k buffers Swap: 2000088k total, 106872k used, 1893216k free, 350780k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 2026 xyz 20 0 396m 207m 7192 R 100 10.3 4:11.58 emulator-arm Desktop: Cpu0 : 0.7%us, 0.0%sy, 0.0%ni, 99.3%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu1 : 1.3%us, 0.0%sy, 0.0%ni, 98.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu2 : 5.0%us, 1.3%sy, 0.0%ni, 91.9%id, 1.7%wa, 0.0%hi, 0.0%si, 0.0%st Cpu3 : 0.3%us, 0.3%sy, 0.0%ni, 99.3%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 7666324k total, 6506808k used, 1159516k free, 1650960k buffers Swap: 8988348k total, 0k used, 8988348k free, 2867300k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 2811 xyz 20 0 392m 220m 6276 S 8 2.9 0:33.58 emulator-arm Is there any way I can improve the emulator performance on the laptop? [UPDATE] I ran the emulator with the same settings, on the same laptop under Win7 and after starting up, it didn't use 100% of a CPU core unlike under linux. Also, I tried running the emulator from a terminal in Linux and I get this message when I don't get it under the desktop Linux host: Could not configure '/dev/hpet' to have a 1024Hz timer. This is not a fatal error, but for better emulation accuracy type: 'echo 1024 /proc/sys/dev/hpet/max-user-freq' as root. I'm not really familiar with rtc or hpet, but it doesn't seem that max-user-freq setting does anything, I still get the same warning.

    Read the article

< Previous Page | 88 89 90 91 92 93 94 95 96 97 98 99  | Next Page >