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  • More CPU cores may not always lead to better performance – MAXDOP and query memory distribution in spotlight

    - by sqlworkshops
    More hardware normally delivers better performance, but there are exceptions where it can hinder performance. Understanding these exceptions and working around it is a major part of SQL Server performance tuning.   When a memory allocating query executes in parallel, SQL Server distributes memory to each task that is executing part of the query in parallel. In our example the sort operator that executes in parallel divides the memory across all tasks assuming even distribution of rows. Common memory allocating queries are that perform Sort and do Hash Match operations like Hash Join or Hash Aggregation or Hash Union.   In reality, how often are column values evenly distributed, think about an example; are employees working for your company distributed evenly across all the Zip codes or mainly concentrated in the headquarters? What happens when you sort result set based on Zip codes? Do all products in the catalog sell equally or are few products hot selling items?   One of my customers tested the below example on a 24 core server with various MAXDOP settings and here are the results:MAXDOP 1: CPU time = 1185 ms, elapsed time = 1188 msMAXDOP 4: CPU time = 1981 ms, elapsed time = 1568 msMAXDOP 8: CPU time = 1918 ms, elapsed time = 1619 msMAXDOP 12: CPU time = 2367 ms, elapsed time = 2258 msMAXDOP 16: CPU time = 2540 ms, elapsed time = 2579 msMAXDOP 20: CPU time = 2470 ms, elapsed time = 2534 msMAXDOP 0: CPU time = 2809 ms, elapsed time = 2721 ms - all 24 cores.In the above test, when the data was evenly distributed, the elapsed time of parallel query was always lower than serial query.   Why does the query get slower and slower with more CPU cores / higher MAXDOP? Maybe you can answer this question after reading the article; let me know: [email protected].   Well you get the point, let’s see an example.   The best way to learn is to practice. To create the below tables and reproduce the behavior, join the mailing list by using this link: www.sqlworkshops.com/ml and I will send you the table creation script.   Let’s update the Employees table with 49 out of 50 employees located in Zip code 2001. update Employees set Zip = EmployeeID / 400 + 1 where EmployeeID % 50 = 1 update Employees set Zip = 2001 where EmployeeID % 50 != 1 go update statistics Employees with fullscan go   Let’s create the temporary table #FireDrill with all possible Zip codes. drop table #FireDrill go create table #FireDrill (Zip int primary key) insert into #FireDrill select distinct Zip from Employees update statistics #FireDrill with fullscan go  Let’s execute the query serially with MAXDOP 1. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --First serially with MAXDOP 1 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 1) goThe query took 1011 ms to complete.   The execution plan shows the 77816 KB of memory was granted while the estimated rows were 799624.  No Sort Warnings in SQL Server Profiler.  Now let’s execute the query in parallel with MAXDOP 0. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --In parallel with MAXDOP 0 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 0) go The query took 1912 ms to complete.  The execution plan shows the 79360 KB of memory was granted while the estimated rows were 799624.  The estimated number of rows between serial and parallel plan are the same. The parallel plan has slightly more memory granted due to additional overhead. Sort properties shows the rows are unevenly distributed over the 4 threads.   Sort Warnings in SQL Server Profiler.   Intermediate Summary: The reason for the higher duration with parallel plan was sort spill. This is due to uneven distribution of employees over Zip codes, especially concentration of 49 out of 50 employees in Zip code 2001. Now let’s update the Employees table and distribute employees evenly across all Zip codes.   update Employees set Zip = EmployeeID / 400 + 1 go update statistics Employees with fullscan go  Let’s execute the query serially with MAXDOP 1. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --Serially with MAXDOP 1 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 1) go   The query took 751 ms to complete.  The execution plan shows the 77816 KB of memory was granted while the estimated rows were 784707.  No Sort Warnings in SQL Server Profiler.   Now let’s execute the query in parallel with MAXDOP 0. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --In parallel with MAXDOP 0 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 0) go The query took 661 ms to complete.  The execution plan shows the 79360 KB of memory was granted while the estimated rows were 784707.  Sort properties shows the rows are evenly distributed over the 4 threads. No Sort Warnings in SQL Server Profiler.    Intermediate Summary: When employees were distributed unevenly, concentrated on 1 Zip code, parallel sort spilled while serial sort performed well without spilling to tempdb. When the employees were distributed evenly across all Zip codes, parallel sort and serial sort did not spill to tempdb. This shows uneven data distribution may affect the performance of some parallel queries negatively. For detailed discussion of memory allocation, refer to webcasts available at www.sqlworkshops.com/webcasts.     Some of you might conclude from the above execution times that parallel query is not faster even when there is no spill. Below you can see when we are joining limited amount of Zip codes, parallel query will be fasted since it can use Bitmap Filtering.   Let’s update the Employees table with 49 out of 50 employees located in Zip code 2001. update Employees set Zip = EmployeeID / 400 + 1 where EmployeeID % 50 = 1 update Employees set Zip = 2001 where EmployeeID % 50 != 1 go update statistics Employees with fullscan go  Let’s create the temporary table #FireDrill with limited Zip codes. drop table #FireDrill go create table #FireDrill (Zip int primary key) insert into #FireDrill select distinct Zip       from Employees where Zip between 1800 and 2001 update statistics #FireDrill with fullscan go  Let’s execute the query serially with MAXDOP 1. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --Serially with MAXDOP 1 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 1) go The query took 989 ms to complete.  The execution plan shows the 77816 KB of memory was granted while the estimated rows were 785594. No Sort Warnings in SQL Server Profiler.  Now let’s execute the query in parallel with MAXDOP 0. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --In parallel with MAXDOP 0 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 0) go The query took 1799 ms to complete.  The execution plan shows the 79360 KB of memory was granted while the estimated rows were 785594.  Sort Warnings in SQL Server Profiler.    The estimated number of rows between serial and parallel plan are the same. The parallel plan has slightly more memory granted due to additional overhead.  Intermediate Summary: The reason for the higher duration with parallel plan even with limited amount of Zip codes was sort spill. This is due to uneven distribution of employees over Zip codes, especially concentration of 49 out of 50 employees in Zip code 2001.   Now let’s update the Employees table and distribute employees evenly across all Zip codes. update Employees set Zip = EmployeeID / 400 + 1 go update statistics Employees with fullscan go Let’s execute the query serially with MAXDOP 1. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --Serially with MAXDOP 1 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 1) go The query took 250  ms to complete.  The execution plan shows the 9016 KB of memory was granted while the estimated rows were 79973.8.  No Sort Warnings in SQL Server Profiler.  Now let’s execute the query in parallel with MAXDOP 0.  --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --In parallel with MAXDOP 0 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 0) go The query took 85 ms to complete.  The execution plan shows the 13152 KB of memory was granted while the estimated rows were 784707.  No Sort Warnings in SQL Server Profiler.    Here you see, parallel query is much faster than serial query since SQL Server is using Bitmap Filtering to eliminate rows before the hash join.   Parallel queries are very good for performance, but in some cases it can hinder performance. If one identifies the reason for these hindrances, then it is possible to get the best out of parallelism. I covered many aspects of monitoring and tuning parallel queries in webcasts (www.sqlworkshops.com/webcasts) and articles (www.sqlworkshops.com/articles). I suggest you to watch the webcasts and read the articles to better understand how to identify and tune parallel query performance issues.   Summary: One has to avoid sort spill over tempdb and the chances of spills are higher when a query executes in parallel with uneven data distribution. Parallel query brings its own advantage, reduced elapsed time and reduced work with Bitmap Filtering. So it is important to understand how to avoid spills over tempdb and when to execute a query in parallel.   I explain these concepts with detailed examples in my webcasts (www.sqlworkshops.com/webcasts), I recommend you to watch them. The best way to learn is to practice. To create the above tables and reproduce the behavior, join the mailing list at www.sqlworkshops.com/ml and I will send you the relevant SQL Scripts.   Register for the upcoming 3 Day Level 400 Microsoft SQL Server 2008 and SQL Server 2005 Performance Monitoring & Tuning Hands-on Workshop in London, United Kingdom during March 15-17, 2011, click here to register / Microsoft UK TechNet.These are hands-on workshops with a maximum of 12 participants and not lectures. For consulting engagements click here.   Disclaimer and copyright information:This article refers to organizations and products that may be the trademarks or registered trademarks of their various owners. Copyright of this article belongs to R Meyyappan / www.sqlworkshops.com. You may freely use the ideas and concepts discussed in this article with acknowledgement (www.sqlworkshops.com), but you may not claim any of it as your own work. This article is for informational purposes only; you use any of the suggestions given here entirely at your own risk.   Register for the upcoming 3 Day Level 400 Microsoft SQL Server 2008 and SQL Server 2005 Performance Monitoring & Tuning Hands-on Workshop in London, United Kingdom during March 15-17, 2011, click here to register / Microsoft UK TechNet.These are hands-on workshops with a maximum of 12 participants and not lectures. For consulting engagements click here.   R Meyyappan [email protected] LinkedIn: http://at.linkedin.com/in/rmeyyappan  

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  • Oracle Linux Delivers Top CPU Benchmark Results on Sun Blades

    - by sergio.leunissen
    From the Performance and Best Practices blog: Fresh SPEC CPU2006 results for Sun Blade X6275 M2 Server Modules running Oracle Linux 5.5. The highlights: The dual-node Sun Blade X6275 M2 server module, equipped with two Intel Xeon X5670 2.93 GHz processors per node and running the Oracle Enterprise Linux 5.5 operating system delivered the best SPECint_rate2006 and SPECfp_rate2006 benchmark results for all systems with Intel Xeon processor 5000 sequence. With a SPECint_rate2006 benchmark result of 679, the Sun Blade X6275 M2 server module, with two compute nodes per blade, delivers maximum performance for space constrained environments. Comparing Oracle's dual-node blade to HP's dual-node blade server, based on their single node performance, the Sun Blade X6275 M2 server module SPECfp_rate2006 score of 241 outperforms the best published HP ProLiant BL2X220c G5 server score by 3.2x. A single node of a Sun Blade X6275 M2 server module using 2.93 GHz Intel Xeon X5670 processors delivered 37% improvement in SPECint_rate2006 benchmark results and 22% improvement in SPECfp_rate2006 benchmark results compared to the previous generation Sun Blade X6275 server module. Both nodes of a Sun Blade X6275 M2 server module using 2.93 GHz Intel Xeon X5670 processors delivered 59% improvement on the SPECint_rate2006 benchmark and 40% improvement on the SPECfp_rate2006 benchmark compared to the previous generation Sun Blade X6275 server module.

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  • Intel CPU: Core 2 Duo vs. Xeon Dual Core. Which is faster?

    - by Clay Nichols
    Xeon: Dual Core Intel® Xeon® W3503 2.40GHz, 4M L3, 4.8GT/s Intel® Core™2 Duo E8400 (6MB,3.0 GHz, 1333FSB), USES: Virtual PC (and doing software development within Virtual PC) A little bit of video editing Desktop software (like Outlook, Quickbooks, etc.) I think #1 is faster, but wanted feedback from other folks here. Which is faster and why? Thanks!

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  • kvm and qemu host: Is there a limit for max CPUs (Ubuntu 10.04)?

    - by Valentin
    Today we encountered a really strange behaviour on two identical kvm and qemu hosts. The host systems each have 4 x 10 Cores, which means that 40 physical cores are displayed as 80 within the operating system (Ubuntu Linux 10.04 64 Bit). We started a Windows 2003 32 Bit VM (1 CPU, 1 GB RAM, we changed those values multiple times) on one of the nodes and noticed that it took 15 minutes until the boot process began. During those 15 minutes, a black screen is shown and nothing happens. libvirt and the host system show that the qemu-kvm process for the guest is almost idling. stracing this process only shows some FUTEX entries, but nothing special. After those 15 minutes, the Windows VM suddenly starts booting and the Windows logo occurs. After a few seconds, the VM is ready to be used. The VM itself is very performant, so this is no performance issue. We tried to pin the CPUs with the virsh and taskset tools, but this only made things worse. When we boot the Windows VM with a Linux Live CD there is also a black screen for several minutes, but not as long as 15. When booting another VM on this host (Ubuntu 10.04) it also has the black screen problem, and also here the black screen is only shown for 2-3 minutes (instead of 15). So, summerinzing this: Each guest on each of those identical nodes suffers from idling a few minutes after being started. After a few minutes, the boot process suddenly starts. We have observed that the idling time happens right after the bios of the guest was initialized. One of our employees had the idea to limit the amount of CPUs with maxcpus=40 (because of 40 physical cores existing) within Grub (kernel parameter) and suddenly the "black-screen-idling"-behaviour disappeared. Searching the KVM and Qemu mailing lists, the internet, forums, serverfault and other various sites for known bugs etc. showed no useful results. Even asking in the dev IRC channels brought no new ideas. The people there recommend us to use CPU pinning, but as stated before it didn't help. My question is now: Is there a sort of limit of CPUs for a qemu or kvm host system? Browsing the source code of those two tools showed that KVM would send a warning if your host has more than 255 CPUs. But we are not even scratching on that limit. Some stuff about the host system: 3.0.0-20-server kvm 1:84+dfsg-0ubuntu16+0.14.0+noroms+0ubuntu4 kvm-pxe 5.4.4-7ubuntu2 qemu-kvm 0.14.0+noroms-0ubuntu4 qemu-common 0.14.0+noroms-0ubuntu4 libvirt 0.8.8-1ubuntu6 4 x Intel(R) Xeon(R) CPU E7-4870 @ 2.40GHz, 10 Cores

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  • AMD Unleashes Six-Core Desktop CPU

    <b>Hardware Central:</b> "AMD today announced the availability of a new six-core desktop processor and platform to accompany it, which includes a new chipset and support for hobbyists who like to tweak their processors to the limits of their heat sink and warranty."

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  • i7 4770k or i7 4930k - Which for faster compile times? [on hold]

    - by Chumm
    I've looked up comparisons and found that single core performance seems to be better on i7 4770k, but has less cores that the i7 4930k. Would VS take advantage of extra cores when compiling, or would the difference be negible. I'm looking to buy the PC primarily for programming, so which would be better for visual studio? I already have the rest of my build ready, I just need to decide on this! :) thanks

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  • High load (and high temp) with idle processes

    - by Nanne
    I've got a semi-old laptop (toshiba satellite a110-228), that's appointed 'laptop for the kids' by my sister. I've installed ubuntu netbook (10.10) on it because of the lack-of memory and it seems to work fine, accept from some heat-issues. These where never a problem under windows. It looks like I've got something similar to this problem: Load is generally 1 or higher, sometimes its stuck at 0.80, but its way to high. Top/htop only show a couple of percentage CPU use (which isn't too shocking, as i'm not doing anything). At this point all the software is stock, and i'd like to keep it that way because its supposed to be the easy-to-maintain kids computer. Now I'd like to find out: What could be the cause of the high load? Could it be as this thread implies, some driver, are there other options to check? How could I see what is really keeping the system hot and bothered? How to check what runs, etc etc? I'd like to pinpoint the culprint. further steps to take for debugging? The big bad internet leads me to believe that it might be the graphics drivers. The laptop has an Intel 945M chipset, but that doesn't seem to be one of the problem childs in this manner (I read a lot abotu ATI drivers that need special isntall). I'd not only welcome hints to directly solve this (duh) but also help in starting to debug what is going on. I am really hesitant in installing an older kernel, as I want it to be stock, and easy upgradeable (because I don't live near it, it should run without me ;) ) As an afterthought: to keep the whole thing cooler, can I 'amp up' the fancontrol? Its only going "airplane" mode when the computer is 95 Celcius, which is a tad late for my taste. Top: powertop:

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  • Ubuntu doesn't load, can't even open a terminal to type commands, even after boot repair

    - by Sky
    When I start Ubuntu I only get my desktop picture and am unable to open a terminal to type any commands. When I try a Guest session all I get is a red Ubuntu backdrop, nothing else. I tried boot repair but no improvement. Summary information following boot repair: http://paste.ubuntu.com/8109809/ I can paste some of it here if someone can tell me which part of it is relevant. This all occurred after I tried to remove compizconfig (which I might not have completed), because it's been using up my CPU (running at 50-60% with compiz at the top in System monitor. My laptop has been running very slow since installing Ubuntu so I've been trying to fix that, also website videos play slow and the startup of Ubuntu has been faulty. I also installed a proprietory Nvidia driver (304) before this launcher issue occurred, in an effort to fix my video problem (didn't help anything). Laptop is Dell 620m with Intel Core 2; 1.83GHz, 2 GB RAM, Ubuntu 14.04 (new to Linux); 66GB Ubuntu partition. Everything works fine on the small XP partition of my laptop, but I've moved all my files to the larger Ubuntu portion. I wanted to try some answers I found to similar questions but they all seem to involve commands in a terminal and I can't open a terminal. How can I get the launcher back, along with access to my programmes etc? Thank you for any help.

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  • How do I throttle a command in a terminal window?

    - by To Do
    I needed to run convert with a lot of images at the same time. The command took quite a while but this doesn't bother me. The issue is that this command rendered my computer unusable while the command was running (for about 15 minutes). So is it possible to throttle the command by limiting resources (processor and memory) to the command, directly from the command line? This can only work if I add something to the same line before pressing Enter because once I start the process the computer slows so much that it is impossible for example to switch to "System monitor" and reduce priority. Edit: top and iotop results I managed to run top and sudo iotop >iotop.txt while doing one of these convert operations. (The iotop.txt file produced is difficult to read) Results of top: PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 14275 username 20 0 4043m 3.0g 1448 D 7.0 80.4 0:16.45 convert Results of iotop: [?1049h[1;24r(B[m[4l[?7h[?1h=[39;49m[?25l[39;49m(B[m[H[2JTotal DISK READ: 1269.04 K/s | Total DISK WRITE:[59G0.00 B/s (B[0;7m TID PRIO USER DISK READ DISK WRITE SWAPIN(B[0;1;7m IO(B[0;7m COMMAND [3;2H(B[m2516 be/4 username 350.08 K/s 0.00 B/s 0.00 % 0.00 % zeitgeist-datahub 7394 be/4 username 568.88 K/s 0.00 B/s 77.41 % 0.00 % --rendere~.530483991[5;1H14275 idle username 350.08 K/s 0.00 B/s 37.49 % 0.00 % convert S~f test.pdf[6;2H2048 be/4 root[6;24H0.00 B/s 0.00 B/s 0.00 % 0.00 % [kworker/3:2] [5G1 be/4 root[7;24H0.00 B/s 0.00 B/s 0.00 % 0.00 % init Furthermore, even after the process ends, the computer does not return to the previous performance. I found a way around this by running sudo swapoff -a followed by sudo swapon -a

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  • Low FPS in some games, but hardware not fully used

    - by Mario De Schaepmeester
    I just did a little funny experiment in the game/sim "Train Simulator 2013". I normally have good FPS in it (around 30) at full settings. What I did was make a really, really long train so that the calculations the sim needed to make were enormous (the sim is quite realistic, it takes all things into account like speed/acceleration, G-forces, comfort levels, possible wheel slip and many more, and most of those things on each carriage seperately). This resulted in only 14FPS as reported by the game, but it felt more like 8FPS or so. I have a Logitech G15 keyboard which has an LCD, and it allows me to monitor CPU/RAM and video card load on it. The strange thing is, all CPU cores were busy, but the total load was only about 60% maximum at all times. The video card was only on 30% load (possibly an important note, the memory was full, which is however not unusual for the game in question). The RAM had plenty of room and there weren't many operations as it didn't grow or shrink much. I just have the feeling that the game would run smoother if it used more of my hardware power. Why is it not doing so? I had the same in another game, The Elder Scrolls: Morrowind when using more than 100 mods (that all use scripting) and a few high res texture mods, + a full-on graphics improvement program. The engine is very old (2003), and so I thought this might be the cause (not being optimised for multithreading). I had thought of possible causes, like: The operating system doesn't let the games use all the resources. It doesn't make use of multi-threading appropriately. To eliminate the former, I tried a CPU stress tool and that got 100% CPU juice as I let it run, so the OS is not the problem. I gave its thread the "higher" priority though. My actual question In both games, I did things the engine was not really built to do or support. Can those games' framerate be limited cause of their own engine not being able to cope? What is the real reason and more importantly, can I help it? And in any case, could something actually be wrong with my hardware? It's all reasonably new, a couple of months, and I (almost) never experience any other trouble. Modern and much more demanding games work absolutely fine. Specs CPU: AMD Phenom II 965 X4 @ 3.4gHz RAM: 8GB of DDR3 RAM Video: MSI GTX560 (nVidia chip) with 1GB of GDDR5 memory OS: Windows 7 Ultimate 64 bit Nothing overclocked.

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  • Unexplained CPU and Disk activity spikes in SQL Server 2005

    - by Philip Goh
    Before I pose my question, please allow me to describe the situation. I have a database server, with a number of tables. Two of the biggest tables contain over 800k rows each. The majority of rows are less than 10k in size, though roughly 1 in 100 rows will be 1 MB but <4 MB. So out of the 1.6 million rows, about 16000 of them will be these large rows. The reason they are this big is because we're storing zip files binary blobs in the database, but I'm digressing. We have a service that runs constantly in the background, trimming 10 rows from each of these 2 tables. In the performance monitor graph above, these are the little bumps (red for CPU, green for disk queue). Once ever minute we get a large spike of CPU activity together with a jump in disk activity, indicated by the red arrow in the screenshot. I've run the SQL Server profiler, and there is nothing that jumps out as a candidate that would explain this spike. My suspicion is that this spike occurs when one of the large rows gets deleted. I've fed the results of the profiler into the tuning wizard, and I get no optimisation recommendations (i.e. I assume this means my database is indexed correctly for my current workload). I'm not overly worried as the server is coping fine in all circumstances, even under peak load. However, I would like to know if there is anything else I can do to find out what is causing this spike? Update: After investigating this some more, the CPU and disk usage spike was down to SQL server's automatic checkpoint. The database uses the simple recovery model, and this truncates the log file at each checkpoint. We can see this demonstrated in the following graph. As described on MSDN, the checkpoints will occur when the transaction log becomes 70% full and we are using the simple recovery model. This has been enlightening and I've definitely learned something!

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  • django, mod_wsgi, MySQL High CPU - Problems

    - by Red Rover
    Good Evening, and thank you for reading this post. I am having a problem with Django after migrating the dB from SQLlite to MySQL. Initially, for the first 48hours, all ran well. But now we are experiencing high cpu about every 30 minutes. This is a production ESX4i VM host, with 2 x 2.8 ghz CPUs and 12 GB ram. I have allocated 4 cpu's to this VM and 4 GB memory. Any insight into this configuration and help with the spikes in CPU would be appreciated. IT is configured to use the prefork MPM. Outlined are the config's for the different services: MySQL Server version: 5.1.61 Source distribution Django 1.3 mod_wsgi Apache/2.2.15 httpd.conf Timeout 120 KeepAlive Off MaxKeepAliveRequests 400 KeepAliveTimeout 3 prefork MPM StartServers 8 MinSpareServers 8 MaxSpareServers 16 ServerLimit 40 MaxClients 40 MaxRequestsPerChild 0 worker MPM StartServers 16 MaxClients 1024 MinSpareThreads 64 MaxSpareThreads 256 ThreadsPerChild 64 MaxRequestsPerChild 10240 MySQL my.conf [mysqld] datadir=/var/lib/mysql socket=/var/lib/mysql/mysql.sock user=mysql symbolic-links=0 [mysqld_safe] log-error=/var/log/mysqld.log pid-file=/var/run/mysqld/mysqld.pid my.cnf wsgi.conf LoadModule wsgi_module modules/mod_wsgi.so /etc/httpd/conf.d/wsgi.conf WSGISocketPrefix /var/run/wsgi WSGIPythonEggs /var/tmp WSGIDaemonProcess SITE maximum-requests=10000 WSGIProcessGroup SITE

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  • CPU / Affinity mask problem in SQL 2005

    - by Robert Moir
    Hi folks, Having a problem with a SQL Server which was virtualised. The CPU mask was set on the physical host for some reason and now advanced options are not available. So I need to reconfigure the CPU affinity mask settings - which are advanced options, so this is blocked because of the affinity mask issue. I've tried doing this from the SQL server in single user command line mode, I've googled and found lots of people with similar problems but no real solution. I'm stumped. Any ideas? Sample commands and output from query analyser below. sp_configure 'show advanced options', 1 GO RECONFIGURE WITH OVERRIDE GO sp_configure 'affinity mask', 0x00000000 GO RECONFIGURE GO ----------------------------------------- Configuration option 'show advanced options' changed from 0 to 1. Run the RECONFIGURE statement to install. Msg 5832, Level 16, State 1, Line 1 The affinity mask specified does not match the CPU mask on this system. Msg 15123, Level 16, State 1, Procedure sp_configure, Line 51 The configuration option 'affinity mask' does not exist, or it may be an advanced option.

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  • Apache process consumes too much CPU

    - by Niro
    I have an ubuntu apache/php server running php doing appx 100 hits/sec and a PHP cron running in the background. I get occasionally high CPU load on one of the Apache processes which stays high regardless of traffic or cron activity. It seems to me that its stuck in some kind of loop or something. Below you will find the top and strace info. How can I find where the bad code is and what causes this? top - 14:45:24 up 3 days, 3:38, 1 user, load average: 5.10, 5.88, 5.85 Tasks: 163 total, 5 running, 158 sleeping, 0 stopped, 0 zombie Cpu(s): 47.8%us, 18.5%sy, 0.0%ni, 10.2%id, 0.0%wa, 0.0%hi, 1.8%si, 21.6%st Mem: 7885012k total, 3858484k used, 4026528k free, 177444k buffers Swap: 0k total, 0k used, 0k free, 1037868k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 10736 www-data 20 0 769m 559m 478m R 69 7.3 29:08.30 apache2 10844 www-data 20 0 824m 601m 492m S 17 7.8 4:37.90 apache2 1016 root 20 0 242m 25m 4628 S 6 0.3 162:07.93 scalarizr 9030 www-data 20 0 879m 619m 492m S 4 8.0 5:06.82 apache2 20216 www-data 20 0 747m 228m 170m S 4 3.0 0:01.94 apache2 10807 www-data 20 0 814m 584m 492m S 3 7.6 4:54.10 apache2 10455 www-data 20 0 831m 574m 492m S 3 7.5 4:32.65 apache2 10495 www-data 20 0 849m 592m 492m S 3 7.7 4:41.10 apache2 10884 www-data 20 0 840m 581m 492m S 3 7.6 4:25.06 apache2 ^CProcess 10736 detached % time seconds usecs/call calls errors syscall ------ ----------- ----------- --------- --------- ---------------- 74.55 0.148052 1 109755 gettimeofday 25.36 0.050370 0 164634 clock_gettime 0.09 0.000178 0 54878 poll ------ ----------- ----------- --------- --------- ---------------- 100.00 0.198600 329267 total root@ec2-67-202-54-36:~# ^C

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  • How CPU communicates with HW

    - by b-gen-jack-o-neill
    Good day. I am new here, but I could not find answer to my question using google, so I help I do not violate any rules. So, basically, all I want to ask is, how CPU comminucates with other HW, such as printers, Graphic card, sound card, LAN card etc. I know, that for basic system I/O, you can use BIOS interrupts. INT 10h I believe is for display output. But, what I would like to know is, what actually happens when you execute instruction int 10h. From desription of int instruction, it should jump to routine, which is stored on adress pointed by adress stored in iterrupt table. But how does this routine get into the RAM? Does BIOS save that routines to the RAM? And what actually that routine does? I mean, CPU can only acess RAM, right? So how can now acess some other HW? Is there some special instrucion for it? Or is CPU somehow connected to BIOS, and than BIOS actually does the work? And the last thing, does even OS like Windows or GNU/Linux use BIOS interrupts, or can OS acess HW directly? Thanks.

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  • ASP.NET Session State SQL Server 2008 R2 Freezes with High CPU Usage

    - by jtseng
    Our ASP.Net website uses SQL Server as the session state provider. We currently host the database on SQL Server 2005 since it does not play well on 2008 R2. We would like to know why, and how to fix it. hardware setup Our current session state server has SQL Server 2005 with the files hosted on a single local disk. It is one of our oldest servers since it has served us well, and we never felt the need to upgrade it. The database is about 2 GB holding 6000 sessions. (The sessions are a little big, but we need it.) We have another server with SQL Server 2008 R2 with a much faster CPU, much more RAM, and a much faster hard disk. situation One day, we have a huge surge in traffic. The transaction log growth on SQL Server freezes the server for 10's of seconds, allowing only a few requests through in minutes. So we load up the new server with ASPState with very large data and log files and point all of our applications to the new server. It chugs along fine for about 5 minutes, and then the CPU usage jumps up to 50% of the 16 cores that Standard Edition can use and freezes for 10's of seconds at a time. The files do not record any autogrowth events. The disk queue is nice and low. RAM usage is low. CPU usage on our old server has never been higher than 5%. What happened on the new server? Alternatively, I would like to hear success stories with ASP.NET session state server running on SQL Server 2008 R2 with an average write load of 30MB/sec with bursts up to 200MB/sec.

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  • Apache/Passenger and cpulimit

    - by Dave Smylie
    I run a ruby on rails site that processes email - the email is dumped directly into the web app via a POST from postfix. At times I can get a burst of email coming in causing a prolonged surge in CPU usage making my VPS provider understandable unhappy with me. These emails don't need to be processed in a timely manner - they just need to be (eventually) processed. Obviously I can't just nice the process as that only looks at the cpu usage on my VPS and can't take into account the cpu usage on the other VPS's. I have found a utility called cpulimit that will you put hard limits on cpu usage for a particular process. (eg 20%). This seems ideal for this purpose, but I can't work out to integrate with apache/passenger. Passenger starts up a ruby process for each server and restarts them periodically. Each time the pid will change. Cpulimit needs to be given a pid number for it to act on. Anyone got any ideas how I could get passenger to fire off a call this command when it's starting up this particular virtual host?

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  • Computer locking up, looking for bootable hardware diagnostic tool.

    - by Carl Menke
    Well today I helped my friend build a computer. All went pretty well until we got to installing Win7. Thing is, we thought, it was crashing constantly. I adjusted pretty much every setting in the BIOS and removed as much hardware as possible to try and prevent a crash. No dice. So far I've tried running an Ubuntu live cd without the harddrive installed. Nope, crashed on boot. And then I just tried Microsoft's ram utility disk and it eventually locked up on that (the ram passed though). So it seems to me like it's either the CPU (AMD PhenomII x3) or the motherboard that could be bad, but I don't know how to test them individually for problems. I thought it could be a overheating issue, but the BIOS reports that the CPU temp is fine idling around 34C. Any advice or diagnostic disk that could help me out? TL;DR: Computer locks up frequently during use (cannot even boot/install an operating system), memory is fine, probably CPU or Mobo, BIOS says CPU temps are fine. What should I try?

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  • Very high-pitched noise when computer does something intense?

    - by Starkers
    "Intense" is the best word I can use to describe it because I'm not sure what it is, whether it's RAM, GPU or CPU. If I pan the camera in unity: A high pitched noise issues from the computer. The picosecond I start panning the sound starts. Stops the picosecond I stop panning. If I start an infinite loop: 2.0.0p247 :016 > x = 1 => 1 2.0.0p247 :017 > while x < 2 do 2.0.0p247 :018 > puts 'huzzah!' 2.0.0p247 :019?> end huzzah! huzzah! huzzah! An identical high pitched noise can be heard. I don't think it's the GPU due to this simple experiment. Or any monitor-weirdness (although the sound does sound like one of those old CRT monitors if you're old enough to be young when those things were about) The CPU? Or maybe my SSD? It's my first SSD and the first time I've heard this noise. Should I be worried? Regardless, what's causing this sound? I can't think what would cause such high frequency vibrations. I built the PC myself. Not enough heat paste on the CPU? Too much? Just no idea what's going on. Info: CPU Type QuadCore Intel Core i5-3570K, 3800 MHz (38 x 100) Motherboard Name Asus Maximus V Extreme Flash Memory Type Samsung 21nm TLC NAND Video Adapter Asus HD7770

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  • How to verify power provided to processors is clean

    - by GregC
    Once in a blue moon, I am seeing a blue screen of death on a shiny new Dell R7610 with a single 1100 Watt Dell-provided power supply on a beefy UPS. BCode is 101 (A clock interrupt was not received...), which some say is caused by under-volting a CPU. Naturally, I would have to contact Dell support, and their natural reaction would be to replace a motherboard, a power supply, or CPU, or a mixture of the above components. In synthetic benchmarks, system memory and CPU, as well as graphics memory and CPU perform admirably, staying up for hours and days. My questions are: Is power supply good enough for the application? Does it provide clean enough power to VRMs on the motherboard? Are VRMs good enough for dual Xeon E5-2665? Does C-states logic work correctly? Is there sufficient current provided to PCIe peripherals, such as disk controllers? P.S. Recently, I've gone through the ordeal with HP. They were nice and professional about it, but root cause was not established, and the HP machine still is less than 100%, giving me a blue screen of death once in a couple of months. Here's what quick web-searching turns up: http://www.sevenforums.com/bsod-help-support/35427-win-7-clock-interrupt-bsod-101-error.html#post356791 It appears Dell has addressed the above issue by clocking PCIe bus down to 5GT/sec in A03 BIOS. My disk controllers support PCIe 3.0, meaning that I would have to re-validate stability. Early testing shows improvements. Further testing shows significant decrease in performance on each of the x16 slots with Dell R7610 with A03 BIOS. But now it's running stable. HP machine has received a microcode update in September 2013 SUM (July BIOS) that makes it stable.

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  • Pc sometimes turns on sometimes not

    - by cprogcr
    Some time ago, the PC gave the same problem. It wouldn't turn on. When i pressed the button, it turned on but showed nothing. I had replaced the CPU and that seemed to work. I didn't use the PC that much, rarely you know. But now, after some time, it gives the same problem. It turns on, the front light is on, it makes the normal noise the pc makes when it's turned on , but if I try to shut it down by holding the power button it just doesn't work. So again, I tried replacing the CPU and it worked again. I kept it all day working, just to be sure, and sometimes I would restart it and it would work again. No problems at all. So I turned it off at night, and next morning it just would make the same problem. So I tried replacing the PSU. And it worked again. Now while I had the PC with the new PSU, i tried to insert the old CPU, and again, it would turn on. The same thing, tried restarting too, and it would work. But this morning the same problem happened. Edit: I also tried another CPU today and yet no signs of working. I don't know now what to think.

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  • Do Hyper-V guests see multiple CPUs (sockets) or multiple CPU cores when assigned more than 1 vCPU?

    - by Filip Kierzek
    I have SQL Server 2008 Express running on Hyper-V based virtual machine with two vCPU-s. I've just been reading up on SQL Server 2012 Express and noticed that it's CPU is "Limited to lesser of 1 Socket or 4 cores" (http://msdn.microsoft.com/en-us/library/cc645993(v=SQL.110).aspx) My question is how do the SQL Server 2012 limits on CPUs/Cores translate into vCPU-s? Are they "processors" or are they "cores"?

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