Careful - note the "long quantum". I wrote this up in one of my books, but I don't have it handy...basically, performance measurement happens in 'ticks'. A tick is (approximately) 10 ms in length.
Obviously LOTS can happen in 10 ms. It used to be that scheduling resolution was in ticks too - but that's no longer the case. Hasn't been for a long time. The general assumption today is that within a tick, multiple processes have moved off and on the processor, you've got some kernel time, some starvation time, etc. etc. However, if you've got processor bound applications, then that assumption may not be valid. You may, in fact, have had only a single task on the processor. In THAT case, resource blocking actually starts happening quite a bit earlier. It can be shown (channeling my statistics prof. from 30 years ago) that resource starvation begins when you have a resource used more than SQRT(2)/2 or basically 71% of the time. This is when it becomes important for you to know your applications. :) Regards, Michael B. Smith Consultant and Exchange MVP http://TheEssentialExchange.com From: James Rankin [mailto:[email protected]] Sent: Thursday, February 03, 2011 9:08 AM To: NT System Admin Issues Subject: Re: Processor Queue Length counter Nice one, thanks for that, I am slowly starting to get my head around this testing and baselining mularkey :-) On 3 February 2011 13:58, Ziots, Edward <[email protected]<mailto:[email protected]>> wrote: James, >From the following M$ Kbase http://technet.microsoft.com/en-us/library/cc768048.aspx * System : Processor Queue Length. Oddly enough, this processor counter shows up under the System object, but not without good reason. There is only 1 queue for tasks that need to go to the processor, even if there is more than one CPU. Thus, counter provides a measure of the instantaneous size of the queue for all processors at the moment that the measurement was taken. The resulting value is a measure of how many threads are in the Ready state waiting to be processed. When dealing with queues, if the value exceeds 2 for a sustained period, you are definitely having a problem with the resource in question. So I would say that a constant value of 40 to 50 would be an issue. Here are some guidelines that are utilized in our RAP ( rapid Assessment Programs) for SQL from Microsoft Premier Engineers. System Processor Queue Length < 4 per CPU For standard servers with long Quantums <= 4 per CPU Excellent < 8 per CPU Good < 12 per CPU Fair So with your 16 CPU ( assuming a QUAD, Quad Core Server, the value you are looking to be under is 64, which you are. So this might defintely be oks here. Z Edward E. Ziots CISSP, Network +, Security + Network Engineer Lifespan Organization Email:[email protected]<mailto:email%[email protected]> Cell:401-639-3505 From: James Rankin [mailto:[email protected]<mailto:[email protected]>] Sent: Thursday, February 03, 2011 8:44 AM To: NT System Admin Issues Subject: Processor Queue Length counter If I have a server with 16 CPUs, and I am measuring the Processor Queue Length counter to check performance, do I need to divide the total queue length by 16 to get a true indication of the level it is at, or is it accurate? I am using Citrix EdgeSight 5.3 to measure this, if it makes any difference. My Processor Queue Length is regularly up to 40 or 50. TIA, JRR -- "On two occasions...I have been asked, 'Pray, Mr Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question." IMPORTANT: This email is intended for the use of the individual addressee(s) named above and may contain information that is confidential, privileged or unsuitable for overly sensitive persons with low self-esteem, no sense of humour or irrational religious beliefs. If you are not the intended recipient, any dissemination, distribution or copying of this email is not authorised (either explicitly or implicitly) and constitutes an irritating social faux pas. Unless the word absquatulation has been used in its correct context somewhere other than in this warning, it does not have any legal or no grammatical use and may be ignored. No animals were harmed in the transmission of this email, although the kelpie next door is living on borrowed time, let me tell you. Those of you with an overwhelming fear of the unknown will be gratified to learn that there is no hidden message revealed by reading this warning backwards, so just ignore that Alert Notice from Microsoft. However, by pouring a complete circle of salt around yourself and your computer you can ensure that no harm befalls you and your pets. If you have received this email in error, please add some nutmeg and egg whites, whisk and place in a warm oven for 40 minutes. ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~ --- To manage subscriptions click here: http://lyris.sunbelt-software.com/read/my_forums/ or send an email to [email protected]<mailto:[email protected]> with the body: unsubscribe ntsysadmin ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~ --- To manage subscriptions click here: http://lyris.sunbelt-software.com/read/my_forums/ or send an email to [email protected]<mailto:[email protected]> with the body: unsubscribe ntsysadmin -- "On two occasions...I have been asked, 'Pray, Mr Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question." IMPORTANT: This email is intended for the use of the individual addressee(s) named above and may contain information that is confidential, privileged or unsuitable for overly sensitive persons with low self-esteem, no sense of humour or irrational religious beliefs. If you are not the intended recipient, any dissemination, distribution or copying of this email is not authorised (either explicitly or implicitly) and constitutes an irritating social faux pas. Unless the word absquatulation has been used in its correct context somewhere other than in this warning, it does not have any legal or no grammatical use and may be ignored. No animals were harmed in the transmission of this email, although the kelpie next door is living on borrowed time, let me tell you. Those of you with an overwhelming fear of the unknown will be gratified to learn that there is no hidden message revealed by reading this warning backwards, so just ignore that Alert Notice from Microsoft. However, by pouring a complete circle of salt around yourself and your computer you can ensure that no harm befalls you and your pets. If you have received this email in error, please add some nutmeg and egg whites, whisk and place in a warm oven for 40 minutes. ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~ --- To manage subscriptions click here: http://lyris.sunbelt-software.com/read/my_forums/ or send an email to [email protected]<mailto:[email protected]> with the body: unsubscribe ntsysadmin ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~ --- To manage subscriptions click here: http://lyris.sunbelt-software.com/read/my_forums/ or send an email to [email protected] with the body: unsubscribe ntsysadmin
