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  • Can a motherboard be faulty even if it's getting power and so are components hooked up to it?

    - by Davy8
    Sort of a followup to this question. The mobo's getting power, the lights are on. The GPU fan is spinning (it doesn't use auxiliary power, it's only connected to the mobo). I'm not getting any video signal, and it's not the video card (nor monitor) that's faulty, so I'm suspecting mobo or CPU (possibly RAM?) and I'm trying to pinpoint which part is at fault. Is the motherboard a candidate for being broken or is it not very likely if it's getting power and powering other components? The CPU fan is getting power as well.

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  • How to find the process(es) which are hogging the machine

    - by Aaron Digulla
    Scenario: All of a sudden, my computer feels sluggish. Mouse moves but windows take ages to open, etc. uptime says the load is 7.69 and raising. What is the fastest way to find out which process(es) are the cause of the load? Now, "top" and similar tools isn't the answer because they either show CPU or memory usage but not both at the same time. What I need is the single command which I might be able to type as it happens - something that will figure out any of System is trying to swap 8GB of RAM to disk because process X ... or process X seeks all over the disk or process X uses 400% CPU" So what I'm looking for is iostat, htop/atop and similar tools run into one with an output like this: 1235 cp - Disk trashing 87 chrome - Uses 2&nbsp;GB of RAM 137 nfs_bench - Uses 95% of the network bandwidth I don't want a tool that gives me some numbers which I can analyze but a tool that tells me exactly which process causes the current load. Assume that the user in front of the keyboard barely knows how to write "process", but the user is quickly overwhelmed when it comes to "resident size", "virtual memory" or "process life cycle". My argument goes like this: A user notices a problem. There can be thousands of reasons ... well, almost :-) The user wants to know the source of the problem. The current solutions give me lots of numbers, and I need to know what these numbers mean. What I'm looking for is a meta tool. 99% of the data is irrelevant to the problem. So what the tool should do is look for processes which hog some resource and list only those along with "this process needs a lot of CPU, this produces many IRQs, this process allocates a lot of RAM (and it's still growing)". This will be a relatively short list. It will be much more simple for someone new to this to locate the culprit from this list than from the output of, say, htop which gives me about 5000 numbers but requires me to fold multi-threaded processes myself (I have 50 lines which say VIRT 2750M but only 16 GB of RAM - the machine ought to swap itself to death but of course, this is a misinterpretation of the data that can happen quickly).

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  • How do I change the output line length from the "top" linux command running in batch mode

    - by Tom
    The following command is useful to capture the current processes that are taking up the most CPU in a file: top -c -b -n 1 > top.log The -c flag is particularly useful because it gives you the command line arguments of each process rather than just the process name. The problem is that each line of output is truncated to fit on the current terminal window. This is ok if you can have a wide terminal because you have a lot of the output but if your terminal is only 165 characters wide, you only get 165 characters of information per process and it is often not enough characters to show the full process command. This is a particular problem when the command is executed without a terminal, for example if you do it via a cron job. Does anyone know how to stop top truncating data or force top to display a certain number of characters per line? This is not urgent because there is an alternative method of getting the top 10 CPU using processes: ps -eo pcpu,pmem,user,args | sort -r -k1 | head -n 10

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  • Good Choice of Memory for Asus K52F-BBR5

    - by Christopher Painter
    I recently purchased an Asus K52F-BBR5 notebook. It's a basic laptop with an Intel P6100 CPU and Mobile Intel® HM55 Express Chipset. It came with 3GB of DDR3 SODIMM memory and I'd like to expand it to 8GB. I'm a little confused by DDR3 nomenclature and not up to date on my knowledge of chipsets. I'd like to make a good choice when selecting memory for it. Crucial's database suggests using either a PC3-8500 with CAS 7 or a PC3-10600 with a CAS of 9. Is the 8500 better because of it's CAS 7 or will my chipset run the memory async at a higher speed and get better performance? Which would be a better choice for my chipset and CPU? Price difference is negligble.

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  • How to set a low process priority for everything spawned from a command prompt in XP?

    - by Binary Worrier
    As a developer, once or twice a week I run a full build on my XP dev machine. This will run at 100% cpu for 30 or 40 minutes, making my machine usless for anything other than basic browsing & email. Is there anyway I can specify that for a given process (i.e. a command prompt) it and any process spawned by it will hae a lower priority, say taking up no more than 60 - 70% of CPU, leaving my machine more usable. I don't mind the build talking 30 or 40% longer, if I still have use of my machine while it's running. Thanks BW P.S. I'd love to be able to throw more hardware at the problem, but that isn't under my control.

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  • Win7 Professional x64 16GB (4.99GB usable)

    - by Killrawr
    I've installed Corsair Vengeance CMZ16GX3M2A1600C10, 2x8GB, DDR3-1600, PC3-12800, CL10, DIMM and my BIOS picks up that there is 16GB, Windows says there is 16GB, CPU-z says there is 16GB. But it only says I can use 4.99GB out of 16GB. Motherboard is P55-GD65 (MS-7583) Supports four unbuffered DIMM of 1.5 Volt DDR3 1066/1333/1600*/2000*/2133* (OC) DRAM, 16GB Max Windows (Above screenshot specifies that I am on a System type: 64-bit OS) CPU-z Microsoft says that the physical memory limit on a 64 bit win7 professional operating system is 192GB. Dxdiag Run Command BIOS Screenshot #1 BIOS Screenshot #2 Why is my OS limiting me to just over a quarter of the available memory? is there anyway to increase it?

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  • Why am I having trouble loading Ubuntu alongside Windows as an application?

    - by STEVE PEAVEY
    I have two good CD ISO files. Both load OK, but when I boot to Ubuntu the screen is fragmented by dozens of white lines. Program works but is useless. I'm running Windows XP SP3 on D201GLY MB, CELERON CPU 220 1.02 GHZ, 512 RAM What could be my problem? CPU? Not enough RAM? Or maybe even the graphics card? to be clearer i am trying to load either ubuntu 8.04 or 9.04 inside windows as an aplication from known GOOD cd's. trying to load with the wubi installer that is loaded on the cd's. sis mirage graphics 32mb vid prosser sis 662.

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  • Server Sizing Methodology

    - by adbrpc
    Our development environment consist of JBoss 5.0.1 DB Server, SQL Server 2008, Oracle IDM. Hardware is Win 2008 32 bit, 4GB RAM. We have reached stage where our environment can not handle application resulting in JBoss shut down throwing out of memory errors and CPU reaching to 90% usage. I am looking methodology to calculate correct server sizing where I input TPS, max number of concurrent users, max CPU utilization etc.. to give me number of servers, RAM size, number of cores. I am expecting application to grow 10% annually. Load Balancer and Failover should also be taken in account while sizing.

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  • Question about getting information off an old HD...

    - by user37983
    Ok so my old cpu was a sony vaio. its kinda old and had xp on it. My gf thrashed it - the cd drive went and she tried fixing it by messing with the configurations bios etc. the actual laptop is really fried the keyboard doesnt work, etc. However the harddrive is still intact. I tried putting the HD in my new cpu (toshiba runnig win7) and it looks like its gonna boot up it goes to the screen with the logo and the status bar starts to load. then it flashes a blue screen for a split second, and goes to the black screen where it says windows did not shut down properly and gives options to (start windows normally, safe mode, safe mode with networking, safe mode with prompts) ive tried every option but it always goes back to this screen. I need to get into the hd cuz i have very important files. is there anyway?

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  • Solr performance (tomcat) - High load

    - by Ward Loockx
    I'm relatively new to solr. I have a production site running on a VPS, but now I'm having serious load issues. I don't know where to start in order to get the load down... VPS specs (linode.com 512) 512 MB RAM 4 CPU (1x priority) Looks like my solr server (tomcat) is using a lot of CPU power You can find my solrconfig.xml on http://pastebin.com/qdfi8Med and my schema.xml on http://pastebin.com/rRusDP8b I've tried to increaese the cache size, but this didn't do anything on the load. You can see the stats page below. EDIT - Because the screenshot was unclear, I took smaller screenshots if what (I think) is important. Dismax query handler stats Caches stats Thanks for the help!

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  • Computer loads BIOS, but won't load OS

    - by LEGEND383
    I have just purchased a brand new motherboard bundle, installed into the old case with the old PSU and the old HDD. I can get into the BIOS, but whenever I try to boot from the HDD, it just sits with the fans going, but nothing is displayed. The moniter works (tested with another machine), and I'd hope there are no problems with the motherboard, CPU or RAM because as I said I only brought them today. The only things I can think of are: The PSU's motherboard connector is a 20-pin, and the motherboard has a 24-pin connector (not a problem with the previous board) The OS is not supported (doesn't seem likly to me, but possible I guess) Here is my system configuration: Motherboard: ASUS F1A55-M le CPU: AMD APU A6 3500 HDD: 1Tb SATA RAM: 4Gb DDR3 OS: Ubuntu Satanic v666.9 PSU: Winpower ATX-400 (this thing is REALLY old) If anyone is able to offer a reason as to why this is not working, or a possible solution, it would be greatly appriciated.

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  • Origin of display connector numbers in XServer (e.g. HDMI1, HDMI2, DP1)

    - by Andreas N
    a custom mainboard has a DVI and a DisplayPort connector on the board. Currently, everything that is connected at DVI will be named "HDMI2" in XServer. I can see that by calling the "xrandr" tool (in Ubuntu Trusty Tahr). A display connected to the DP connector will be named "DP1" or "HDMI1", if I use a DP-to-DVI adapter. We are now testing a slightly upgraded board version, which has a newer CPU (Intel J1800, Baytrail) among other things and the position of the DVI and DP connectors are switched. Also, everything at the DVI port is called "HDMI1" and something connected to the DP port gets "DP2" or "HDMI2". Q: What causes these numbers to be produced in this manner and where (probably in the kernel) is it happening? I suspect the cause to be hardware related. Specifically, at which CPU pins the connector pins are routed and attached to. Q: Would it be possible to influence this numbering scheme in order to retain the previous numbering behaviour?

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  • What is this PHP process? It is crippling my server

    - by user1019588
    This process has been using 65% of my site CPU and has lasted for about 10 minutes now (aren't processes only supposed to go for a couple seconds?) It is obviously something with mysql. This makes sense because I have a lot of queries going, but something still seems a bit odd... This could have something to do with my bad PDO connection that I mentioned in the previous question. Perhaps I am opening too many connections or something like that? Here is the stats on it: Owner: mysql Priority: 0 CPU %: 61.1 Memory %: 0.4 Command:/usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql --plugin-dir=/usr/lib64/mysql/plugin --user=mysql --log-error=/var/lib/mysql/cvps54834319.myhost.com.err --pid-file=/var/lib/mysql/cvps54834319.myhost.com.pid Thanks for any help on this. I have over 10GHZ on my server so this is very concerning to me.

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  • Why are browsers so heavy?

    - by Kaivosukeltaja
    Back in 1998 I had a computer with 233MHz Pentium MMX CPU and a GFX card with no 3D acceleration. It was able to run games like Quake II at a decent FPS rate. My current computer has tons more performance and a mid-class GPU, yet struggles to reach 20 FPS when rendering a single model inside a skybox with WebGL. Even regular pages with lots of 2D CSS animations bring many modern computers to their metaphorical knees. As a web developer I understand there's a lot going on in a web page but not what makes it that heavy. Modern browsers compile JavaScript to CPU native machine code before running it and rendering into a canvas element shouldn't trigger DOM rebuilds so theoretically it should be a lot faster than it is. What am I missing here and is it possible to avoid or minimize whatever is making the browsers slow to build more efficient websites?

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  • Visual Studio 2012 intermittent lockup

    - by user1892678
    Visual Studio 2012 intermittently locks up on me. I notice that devenv.exe jumps to 50% CPU utilization. The CPU stays at this level for a few minutes and then drops. While its at 50% utilization I can still use the IDE. However, intermittently it stops responding (as though it was performing some sort of background process). It only lasts for a few seconds. Also this happens when debugging. I'm running under Windows 7 and I'm using Telerik controls. I've disabled add-ins and extensions and have had no success. Any ideas would be appreciated? Thanks

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  • Ubuntu server header timeout

    - by Tabatha M
    I'm running Ubuntu Linux 12.04.1 Kernel and CPU Linux 3.2.0-30-generic on x86_64. Intel(R) Xeon(R) CPU E31230 @ 3.20GHz, 8 cores I recently came across this problem. I'm using apache2/php latest and when I run $url_headers = @get_headers($url); Inside PHP it would normally take milliseconds to within a second to get the headers. Now recently it can take up to 15 seconds or even timeout. It has worked great for over a year and recently started doing this. I'm not sure how to go about fixing it, any help would be greatly appreciated. Thank you

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  • what may cause unexpected log outs?

    - by lalebarde
    Sometimes, my Linux PC unexpectedly closes my session (log out) while I am working, and puts me back the login window. If I have terminal 1 logged with root and 2 logged with another user (without X), these ones are not logged out. For example, for the last three hours, it has happened five times. Other times, it leads to a reboot. So I have investigated: the UPS, but the behaviour is unchanged without it). the temperatures, but everything is fine (cpu, disks, video card). I have started to investigate also: the memory (partially tested - I have to run a full testyt next night). EDIT: totally tested and passed. My configuration is: Linux 2.6.37-tuxonice x86_64 Intel(R) Core(TM) i7 CPU 860 @ 2.80GHz. Any idea please?

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  • Site faster on 1 core/1GB ram than on 8 core/32GB ram wth?

    - by xtra
    Both sites are US based. I'm located in Europe. http://198.105.209.13/ <==== site that loads tons faster on 1 core and 1gb ram ONLY (Cent OS VPS) http://108.61.35.219/ <== site is located on my dedicated server with i7-3770 cpu and 32 gb ram (Windows) and is slow as hell Even if faster site is on linux it shouldn't make such a big difference in page load seriously. Does anyone know what could be a hiccup on the dedicated server? It's just unbelievable to me that site loads faster on 1 core cpu than on dedicated server. Note that site is pretty much only thing running on dedicated server. It has 1gbps connection.

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  • Why do some servers have so many processes running?

    - by Xeoncross
    I have two VPS servers but they have drastically different amounts of memory usage and processes running. I'm still new to running linux servers so I'm having trouble figuring out what is going on and what I can do to fix it. Both are Debian 5 32bit installs. On one server with 128MB of ram and a single CPU core I have a full server running in only 84MB of RAM. The other server has 512MB (quad core CPU) and it has nothing running but core processes yet its still using 94MB of RAM. Does one have a different kind of virtualization technology that requires more linux core processes or what?

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  • What can i do when my Ubuntu stucked [closed]

    - by Avihai Marchiano
    From time to time firefox cause to my Ubuntu machine to stuck.(nothing run on the machine except firefox) I cant move the mouse or move windows by keyboard. In some cases i have wait for a few minutes and than close last open tab in firefox and it solve the problem in other cases i do restart. Is there any way to prevent it, limit forefox in some way? In windows in most cased even with 100% cpu you can do alt-ctrl-delete and get the task manager, is there a top priority combination in linux that give you terminal? Or any other way ... Run on Ubuntux86 with GNOME , 2GB RAM, dual core cpu

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  • SQL SERVER – Configure Management Data Collection in Quick Steps – T-SQL Tuesday #005

    - by pinaldave
    This article was written as a response to T-SQL Tuesday #005 – Reporting. The three most important components of any computer and server are the CPU, Memory, and Hard disk specification. This post talks about  how to get more details about these three most important components using the Management Data Collection. Management Data Collection generates the reports for the three said components by default. Configuring Data Collection is a very easy task and can be done very quickly. Please note: There are many different ways to get reports generated for CPU, Memory and IO. You can use DMVs, Extended Events as well Perfmon to trace the data. Keeping the T-SQL Tuesday subject of reporting this post is created to give visual tutorial to quickly configure Data Collection and generate Reports. From Book On-Line: The data collector is a core component of the Data Collection platform for SQL Server 2008 and the tools that are provided by SQL Server. The data collector provides one central point for data collection across your database servers and applications. This collection point can obtain data from a variety of sources and is not limited to performance data, unlike SQL Trace. Let us go over the visual tutorial on how quickly Data Collection can be configured. Expand the management node under the main server node and follow the direction in the pictures. This reports can be exported to PDF as well Excel by writing clicking on reports. Now let us see more additional screenshots of the reports. The reports are very self-explanatory  but can be drilled down to get further details. Click on the image to make it larger. Well, as we can see, it is very easy to configure and utilize this tool. Do you use this tool in your organization? Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: SQL Reporting, SQL Reports

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  • SQL SERVER – Identify Most Resource Intensive Queries – SQL in Sixty Seconds #028 – Video

    - by pinaldave
    During performance tuning conversation the very first question people often ask is what are the queries offending the server or in another word let us identify the queries which are the most resource intensive. The resources are often described as either Memory, CPU or IO. When we talk about the queries the same is applicable for them as well. The query which is doing lots of reads or writes are for sure resource intensive as well query which are taking maximum CPU time. Performance tuning is a very deep subject and we all have our own preference regarding what should be the first step to tuning and what should be looked with the salt of grain. Though there is no denying that a query which uses more resources than what it should be using for sure require tuning. There are many ways to do identify query using intense resources (e.g. Extended events etc) but in this one we will go by simple DMV. There is a small gotcha we all have to remember about usage of DMV is that it only brings back results from existing cache. So if you have a query which is very resource intensive but is not cached or if you have explicitly removed the query from the cache it will be not part of the result returned by this DMV. It is quite possible that a query is aged and removed from the cache if your cache is not huge. If your cache is large you may want to be careful in running this query during business hours as this query itself can be resource intensive. Get Script to identify resource intensive query from Here Related Tips in SQL in Sixty Seconds: SQL SERVER – Find Most Expensive Queries Using DMV Simple Example to Configure Resource Governor – Introduction to Resource Governor SQL SERVER – DMV – sys.dm_exec_query_optimizer_info – Statistics of Optimizer SQL SERVER – Wait Stats – Wait Types – Wait Queues – Day 0 of 28 Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Database, Pinal Dave, PostADay, SQL, SQL Authority, SQL in Sixty Seconds, SQL Query, SQL Scripts, SQL Server, SQL Server Management Studio, SQL Tips and Tricks, T SQL, Technology, Video Tagged: Excel

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  • Option Trading: Getting the most out of the event session options

    - by extended_events
    You can control different aspects of how an event session behaves by setting the event session options as part of the CREATE EVENT SESSION DDL. The default settings for the event session options are designed to handle most of the common event collection situations so I generally recommend that you just use the defaults. Like everything in the real world though, there are going to be a handful of “special cases” that require something different. This post focuses on identifying the special cases and the correct use of the options to accommodate those cases. There is a reason it’s called Default The default session options specify a total event buffer size of 4 MB with a 30 second latency. Translating this into human terms; this means that our default behavior is that the system will start processing events from the event buffer when we reach about 1.3 MB of events or after 30 seconds, which ever comes first. Aside: What’s up with the 1.3 MB, I thought you said the buffer was 4 MB?The Extended Events engine takes the total buffer size specified by MAX_MEMORY (4MB by default) and divides it into 3 equally sized buffers. This is done so that a session can be publishing events to one buffer while other buffers are being processed. There are always at least three buffers; how to get more than three is covered later. Using this configuration, the Extended Events engine can “keep up” with most event sessions on standard workloads. Why is this? The fact is that most events are small, really small; on the order of a couple hundred bytes. Even when you start considering events that carry dynamically sized data (eg. binary, text, etc.) or adding actions that collect additional data, the total size of the event is still likely to be pretty small. This means that each buffer can likely hold thousands of events before it has to be processed. When the event buffers are finally processed there is an economy of scale achieved since most targets support bulk processing of the events so they are processed at the buffer level rather than the individual event level. When all this is working together it’s more likely that a full buffer will be processed and put back into the ready queue before the remaining buffers (remember, there are at least three) are full. I know what you’re going to say: “My server is exceptional! My workload is so massive it defies categorization!” OK, maybe you weren’t going to say that exactly, but you were probably thinking it. The point is that there are situations that won’t be covered by the Default, but that’s a good place to start and this post assumes you’ve started there so that you have something to look at in order to determine if you do have a special case that needs different settings. So let’s get to the special cases… What event just fired?! How about now?! Now?! If you believe the commercial adage from Heinz Ketchup (Heinz Slow Good Ketchup ad on You Tube), some things are worth the wait. This is not a belief held by most DBAs, particularly DBAs who are looking for an answer to a troubleshooting question fast. If you’re one of these anxious DBAs, or maybe just a Program Manager doing a demo, then 30 seconds might be longer than you’re comfortable waiting. If you find yourself in this situation then consider changing the MAX_DISPATCH_LATENCY option for your event session. This option will force the event buffers to be processed based on your time schedule. This option only makes sense for the asynchronous targets since those are the ones where we allow events to build up in the event buffer – if you’re using one of the synchronous targets this option isn’t relevant. Avoid forgotten events by increasing your memory Have you ever had one of those days where you keep forgetting things? That can happen in Extended Events too; we call it dropped events. In order to optimizes for server performance and help ensure that the Extended Events doesn’t block the server if to drop events that can’t be published to a buffer because the buffer is full. You can determine if events are being dropped from a session by querying the dm_xe_sessions DMV and looking at the dropped_event_count field. Aside: Should you care if you’re dropping events?Maybe not – think about why you’re collecting data in the first place and whether you’re really going to miss a few dropped events. For example, if you’re collecting query duration stats over thousands of executions of a query it won’t make a huge difference to miss a couple executions. Use your best judgment. If you find that your session is dropping events it means that the event buffer is not large enough to handle the volume of events that are being published. There are two ways to address this problem. First, you could collect fewer events – examine you session to see if you are over collecting. Do you need all the actions you’ve specified? Could you apply a predicate to be more specific about when you fire the event? Assuming the session is defined correctly, the next option is to change the MAX_MEMORY option to a larger number. Picking the right event buffer size might take some trial and error, but a good place to start is with the number of dropped events compared to the number you’ve collected. Aside: There are three different behaviors for dropping events that you specify using the EVENT_RETENTION_MODE option. The default is to allow single event loss and you should stick with this setting since it is the best choice for keeping the impact on server performance low.You’ll be tempted to use the setting to not lose any events (NO_EVENT_LOSS) – resist this urge since it can result in blocking on the server. If you’re worried that you’re losing events you should be increasing your event buffer memory as described in this section. Some events are too big to fail A less common reason for dropping an event is when an event is so large that it can’t fit into the event buffer. Even though most events are going to be small, you might find a condition that occasionally generates a very large event. You can determine if your session is dropping large events by looking at the dm_xe_sessions DMV once again, this time check the largest_event_dropped_size. If this value is larger than the size of your event buffer [remember, the size of your event buffer, by default, is max_memory / 3] then you need a large event buffer. To specify a large event buffer you set the MAX_EVENT_SIZE option to a value large enough to fit the largest event dropped based on data from the DMV. When you set this option the Extended Events engine will create two buffers of this size to accommodate these large events. As an added bonus (no extra charge) the large event buffer will also be used to store normal events in the cases where the normal event buffers are all full and waiting to be processed. (Note: This is just a side-effect, not the intended use. If you’re dropping many normal events then you should increase your normal event buffer size.) Partitioning: moving your events to a sub-division Earlier I alluded to the fact that you can configure your event session to use more than the standard three event buffers – this is called partitioning and is controlled by the MEMORY_PARTITION_MODE option. The result of setting this option is fairly easy to explain, but knowing when to use it is a bit more art than science. First the science… You can configure partitioning in three ways: None, Per NUMA Node & Per CPU. This specifies the location where sets of event buffers are created with fairly obvious implication. There are rules we follow for sub-dividing the total memory (specified by MAX_MEMORY) between all the event buffers that are specific to the mode used: None: 3 buffers (fixed)Node: 3 * number_of_nodesCPU: 2.5 * number_of_cpus Here are some examples of what this means for different Node/CPU counts: Configuration None Node CPU 2 CPUs, 1 Node 3 buffers 3 buffers 5 buffers 6 CPUs, 2 Node 3 buffers 6 buffers 15 buffers 40 CPUs, 5 Nodes 3 buffers 15 buffers 100 buffers   Aside: Buffer size on multi-processor computersAs the number of Nodes or CPUs increases, the size of the event buffer gets smaller because the total memory is sub-divided into more pieces. The defaults will hold up to this for a while since each buffer set is holding events only from the Node or CPU that it is associated with, but at some point the buffers will get too small and you’ll either see events being dropped or you’ll get an error when you create your session because you’re below the minimum buffer size. Increase the MAX_MEMORY setting to an appropriate number for the configuration. The most likely reason to start partitioning is going to be related to performance. If you notice that running an event session is impacting the performance of your server beyond a reasonably expected level [Yes, there is a reasonably expected level of work required to collect events.] then partitioning might be an answer. Before you partition you might want to check a few other things: Is your event retention set to NO_EVENT_LOSS and causing blocking? (I told you not to do this.) Consider changing your event loss mode or increasing memory. Are you over collecting and causing more work than necessary? Consider adding predicates to events or removing unnecessary events and actions from your session. Are you writing the file target to the same slow disk that you use for TempDB and your other high activity databases? <kidding> <not really> It’s always worth considering the end to end picture – if you’re writing events to a file you can be impacted by I/O, network; all the usual stuff. Assuming you’ve ruled out the obvious (and not so obvious) issues, there are performance conditions that will be addressed by partitioning. For example, it’s possible to have a successful event session (eg. no dropped events) but still see a performance impact because you have many CPUs all attempting to write to the same free buffer and having to wait in line to finish their work. This is a case where partitioning would relieve the contention between the different CPUs and likely reduce the performance impact cause by the event session. There is no DMV you can check to find these conditions – sorry – that’s where the art comes in. This is  largely a matter of experimentation. On the bright side you probably won’t need to to worry about this level of detail all that often. The performance impact of Extended Events is significantly lower than what you may be used to with SQL Trace. You will likely only care about the impact if you are trying to set up a long running event session that will be part of your everyday workload – sessions used for short term troubleshooting will likely fall into the “reasonably expected impact” category. Hey buddy – I think you forgot something OK, there are two options I didn’t cover: STARTUP_STATE & TRACK_CAUSALITY. If you want your event sessions to start automatically when the server starts, set the STARTUP_STATE option to ON. (Now there is only one option I didn’t cover.) I’m going to leave causality for another post since it’s not really related to session behavior, it’s more about event analysis. - Mike Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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  • Is recursion really bad?

    - by dotneteer
    After my previous post about the stack space, it appears that there is perception from the feedback that recursion is bad and we should avoid deep recursion. After writing a compiler, I know that the modern computer and compiler are complex enough and one cannot automatically assume that a hand crafted code would out-perform the compiler optimization. The only way is to do some prototype to find out. So why recursive code may not perform as well? Compilers place frames on a stack. In additional to arguments and local variables, compiles also need to place frame and program pointers on the frame, resulting in overheads. So why hand-crafted code may not performance as well? The stack used by a compiler is a simpler data structure and can grow and shrink cleanly. To replace recursion with out own stack, our stack is allocated in the heap that is far more complicated to manage. There could be overhead as well if the compiler needs to mark objects for garbage collection. Compiler also needs to worry about the memory fragmentation. Then there is additional complexity: CPUs have registers and multiple levels of cache. Register access is a few times faster than in-CPU cache access and is a few 10s times than on-board memory access. So it is up to the OS and compiler to maximize the use of register and in-CPU cache. For my particular problem, I did an experiment to rewrite my c# version of recursive code with a loop and stack approach. So here are the outcomes of the two approaches:   Recursive call Loop and Stack Lines of code for the algorithm 17 46 Speed Baseline 3% faster Readability Clean Far more complex So at the end, I was able to achieve 3% better performance with other drawbacks. My message is never assuming your sophisticated approach would automatically work out better than a simpler approach with a modern computer and compiler. Gage carefully before committing to a more complex approach.

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  • system overrides my mount parameters in /etc/fstab

    - by valya
    [.../~]$ mount /dev/sda4 on / type ext4 (rw,commit=60,commit=0) [.../~]$ cat /etc/fstab # UNCONFIGURED FSTAB FOR BASE SYSTEM UUID=70739c04-fcb6-4747-803c-824f9c894f41 / ext4 defaults,commit=60 0 1 What can I do about it? It seems strange. I want to be able to set any commit time I want Edit: added /proc/mounts contents [.../~]$ cat /proc/mounts rootfs / rootfs rw 0 0 none /sys sysfs rw,nosuid,nodev,noexec,relatime 0 0 none /proc proc rw,nosuid,nodev,noexec,relatime 0 0 none /dev devtmpfs rw,relatime,size=886332k,nr_inodes=221583,mode=755 0 0 none /dev/pts devpts rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000 0 0 fusectl /sys/fs/fuse/connections fusectl rw,relatime 0 0 /dev/disk/by-uuid/70739c04-fcb6-4747-803c-824f9c894f41 / ext4 rw,relatime,barrier=1,data=ordered 0 0 none /sys/kernel/debug debugfs rw,relatime 0 0 none /sys/kernel/security securityfs rw,relatime 0 0 none /dev/shm tmpfs rw,nosuid,nodev,relatime 0 0 none /var/run tmpfs rw,nosuid,relatime,mode=755 0 0 none /var/lock tmpfs rw,nosuid,nodev,noexec,relatime 0 0 /dev/sda3 /media/megahard fuseblk rw,nosuid,nodev,relatime,user_id=0,group_id=0,allow_other,blksize=4096 0 0 cgroup /dev/cgroup/cpu cgroup rw,relatime,cpu,release_agent=/usr/local/sbin/cgroup_clean 0 0 gvfs-fuse-daemon /home/va1en0k/.gvfs fuse.gvfs-fuse-daemon rw,nosuid,nodev,relatime,user_id=1000,group_id=1000 0 0

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