Re: Sound skipping problems

On Wed, 8 Jun 2005, Jeff Roberson wrote:

> On Wed, 8 Jun 2005, Jean-Yves Lefort wrote:
>
> > On Wed, 8 Jun 2005 09:57:15 -0400 (EDT)
> > Jeff Roberson <jroberson_at_chesapeake.net> wrote:
> >
> > > On Wed, 8 Jun 2005, Jean-Yves Lefort wrote:
> > >
> > > > On Wed, 8 Jun 2005 12:48:44 +0200
> > > > Simon Barner <barner_at_FreeBSD.org> wrote:
> > > >
> > > > > Jeff Roberson wrote:
> > > > > > I have a patch that should greatly improve the sound skipping problems
> > > > > > people have under heavy io load.  Several people sent me traces that
> > > > > > showed the buf daemon running for hundreds of milliseconds with Giant
> > > > > > held, which can hold up the pcm code.  The patch is available at:
> > > > > >
> > > > > > http://www.chesapeake.net/~jroberson/flushbuf.diff
> > > > >
> > > > > [...]
> > > > >
> > > > > Can I use the patch on 5.4-STABLE? It applies cleanly (with offset,
> > > > > though), but I prefer to ask before doing useless tests.
> > > >
> > > > I've just tested it on 5.4-RELEASE, and it causes the system to hang
> > > > after a few seconds of heavy disk I/O.
> > >
> > > I have updated the patch to partially revert some earlier behavior.  The
> > > hang didn't happen on my machine because I have more memory, but I'm
> > > confident of the cause.  I updated it in place, feel free to try it on
> > > current or 5.x.
> >
> > This one works, and completely removes the sound jitter that used to
> > appear under heavy disk I/O (eg. untarring a 50 megs tarball).
> >
> > Congratulations!
>
> Thanks.  I'd like to get some more experience with it under extreme load
> conditions, but I do eventually plan to MFC.

I made one more slight change to the patch which should reduce the number
of times we needlessly scan the list.  Can you make sure it does not cause
any problems for you?

>
> >
> > PS: if no problems show up, do you intend to MFC this patch?
> >
> > --
> > Jean-Yves Lefort
> >
> > jylefort_at_FreeBSD.org
> > http://lefort.be.eu.org/
> >
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