Re: Voluntary Kernel Preemption Patch

From: Con Kolivas
Date: Mon Jul 12 2004 - 19:28:21 EST


Andrew Morton writes:

Paul Davis <paul@xxxxxxxxxxxxxxxxxxxxx> wrote:

>resierfs: yes, it's a problem. I "fixed" it multiple times in 2.4, but the
>fixes ended up breaking the fs in subtle ways and I eventually gave up.

andrew, this is really helpful. should we conclude that until some
announcement from reiser that they have addressed this, the reiserfs
should be avoided on low latency systems?


It seems that way, yes. I do not know how common the holdoffs are in real
life. It would be interesting if there was a user report that switching
from reiserfs to ext2/ext3 actually made a difference - this would tell us
that it is indeed a real-world problem.

Note that this info because available because someone set
/proc/asound/*/*/xrun_debug. We need more people doing that

Can I just point out that the reiserfs3.6 delays that I originally reported with the preempt threshhold test did not come up once the patch was fixed. I have my preempt threshold set at 1ms and did not see one single reiserfs dump in my syslog. ie I don't think I am personally seeing any significant reiserfs3.6 latencies.

Cheers,
Con

Attachment: pgp00000.pgp
Description: PGP signature