Date: Thu, 10 Jan 2008 08:32:12 +0100 From: Kris Kennaway <kris@FreeBSD.org> To: "J.R. Oldroyd" <fbsd@opal.com> Cc: freebsd-stable@freebsd.org Subject: Re: 7.0BETA4 desktop system also periodically freezes Message-ID: <4785C9FC.4090102@FreeBSD.org> In-Reply-To: <20080109235819.7707133d@linwhf.opal.com> References: <1199812249.96494.133.camel@predator-ii.buffyverse> <4783C8A8.2090705@raad.tartu.ee> <4783D41B.3000204@FreeBSD.org> <4783D748.1050401@raad.tartu.ee> <4783D824.1050502@FreeBSD.org> <4783DB72.6030605@raad.tartu.ee> <4783DCAA.1080108@FreeBSD.org> <4783EA7E.1050008@raad.tartu.ee> <4783ED15.1060606@FreeBSD.org> <20080109141859.74d08743@linwhf.opal.com> <478522B5.5030101@FreeBSD.org> <20080109235819.7707133d@linwhf.opal.com>
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J.R. Oldroyd wrote: > On Wed, 09 Jan 2008 20:38:29 +0100, Kris Kennaway <kris@freebsd.org> wrote: >> >> OK, same requests as to the others then. >> > > I presume you mean hwpmc... LOCK_PROFILING, sched_graph, hwpmc. > In setting that up, I may have stumbled upon a possible cause. > I ran pmcstat for a while and ended up with a very large output > file. Having not noticed any freezes during that time, I decided > to start over with the output to a different filesystem with more > free space. When I removed that first output file, the resulting > disk i/o for the block deallocation caused a very similar freeze > for a few seconds. And when it came back, the load average graph > peaked up, just as before. > > This appears to be repeatable: > > 1. create a very large file, say 1Gb or so > 2. remove it > 3. observe freeze during file dealloc i/o activity > > This on an ata drive, ufs filesystem with softupdates. > > Folk complaining of jerky mouse syndrome (e.g., during compilations) > may be seeing the same - the compiler creates and removes lots of > files. Yeah, this fits with my & kib's hypothesis. > I'm not sure how this would explain those longer freezes (30s or > several minutes) though. No idea, sans data. Kris
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