7.0BETA4 desktop system also periodically freezes

Kris Kennaway kris at FreeBSD.org
Wed Jan 9 23:32:14 PST 2008

J.R. Oldroyd wrote:
> On Wed, 09 Jan 2008 20:38:29 +0100, Kris Kennaway <kris at 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.


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