7.0BETA4 desktop system also periodically freezes

J.R. Oldroyd fbsd at opal.com
Wed Jan 9 20:58:33 PST 2008

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...

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

I'm not sure how this would explain those longer freezes (30s or
several minutes) though.
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