Re: Confirmation Needed - Run Queues include both running and waiting processes
Date: Fri, 8 Mar 2013 00:24:44 +0800
Message-ID: <CAMNBsZs5AtVej6q1O=vHf9WRtyCnPLgeUkSA719am-0XXOGG9A_at_mail.gmail.com>
Yes. My understanding of RunQueue -- particularly or specifically on Linux -- is that it includes "Running" and "Runnable" (wiating for CPU) processes. And that is from a number of observations ! Search google for "sar -r" and you find only the man pages which do NOT indicate that it includes running processes.
My thumb rule is "start monitoring when RunQueue is 2x the number of cores. Get worried when it is 3x the number of cores".
Hemant
On Fri, Mar 8, 2013 at 12:10 AM, <Christopher.Taylor2_at_parallon.net> wrote:
> According to this blogger (and I have no reason to doubt it really) the
> RunQueue length as reported by sar includes *both* processes on CPU and
> processes waiting for CPU.
>
> http://shallahamer-orapub.blogspot.com/2010/07/os-cpu-run-queue-not-what-it-appears.html
>
> (Particularly on Linux)
>
> Can anyone confirm or deny? Based on my review of sar reports over 24
> hours it appears to be the case but not 100% positive. (I'm basically just
> looking for confirmation before I file it away as fact)
>
> (It appears after doing some more research that this is a very muddy
> issue:
> http://hoopercharles.wordpress.com/2010/06/14/cpu-run-queue-what-is-wrong-with-this-quote/)
>
> It appears that sar RunQueue includes both processes in memory and those
> waiting for CPU so that runqueue should be concerning only when RQ passes #
> of CPUs on host and is sustained for 'x' amount of time. (where X is
> defined by the admin). Is that basically correct?
>
>
>
>
> Chris Taylor
> Oracle DBA
> Parallon IT&S
>
>
> --
> http://www.freelists.org/webpage/oracle-l
>
>
>
-- Hemant K Chitale http://hemantoracledba.blogspot.com http://hemantscribbles.blogspot.com http://web.singnet.com.sg/~hkchital -- http://www.freelists.org/webpage/oracle-lReceived on Thu Mar 07 2013 - 17:24:44 CET