Date: Sun, 1 Feb 2004 18:07:38 -0500 (EST) From: Jeff Roberson <jroberson@chesapeake.net> To: Bruce Evans <bde@zeta.org.au> Cc: cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/kern sched_4bsd.c Message-ID: <20040201180709.V36463-100000@mail.chesapeake.net> In-Reply-To: <20040201165625.U7412@gamplex.bde.org>
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On Sun, 1 Feb 2004, Bruce Evans wrote: > On Sat, 31 Jan 2004, Don Lewis wrote: > > > On 31 Jan, Jeff Roberson wrote: > > > jeff 2004/01/31 18:46:47 PST > > > > > > FreeBSD src repository > > > > > > Modified files: > > > sys/kern sched_4bsd.c > > > Log: > > > - Keep a variable 'sched_tdcnt' that is used for the local implementation > > > of sched_load(). This variable tracks the number of running and runnable > > > non ithd threads. This removes the need to traverse the proc table and > > > discover how many threads are runnable. > > Traversing the run queues in sched_load() every 5 seconds might be more > efficient than maintaing the count. It might be cheaper, but it is less scalable. > > > I was suprised to find that processes in disk wait are no longer counted > > towards the load average. This happened in rev 1.163 of kern_synch.c, > > which was committed more than two years ago. > > > > Even if CPU time is available, a machine with a lot of processes stuck > > in disk wait is going to feel slow ... > > They were never counted AFAIK. Isn't this one of the main visible > differences between BSD and Linux? Rev.1.163 ov kern_synch.c just moved > stuff. The change before this in rev.1.59 of vm_meter.c is more likely > to have changed this but was supposed to just remove dead code. > > Bruce >
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