Re: [Bugme-new] [Bug 7027] New: CD Ripping speeds slow with 2.6.17

Mike Galbraith
2006-08-20T06:19:43Z

On Sat, 2006-08-19 at 11:14 -0700, Andrew Morton wrote:
> On Sat, 19 Aug 2006 11:00:22 -0700
> bugme-daemon@bugzilla.kernel.org wrote:
>
> > http://bugzilla.kernel.org/show_bug.cgi?id=7027
> >
> > Summary: CD Ripping speeds slow with 2.6.17
> > Kernel Version: 2.6.17
> > Status: NEW
> > Severity: normal
> > Owner: bzolnier@gmail.com
> > Submitter: brnewber@gmail.com
> >
> >
> > Most recent kernel where this bug did not occur: 2.6.16
> > Distribution: Gentoo
> > Hardware Environment: ASUS K8V mobo, AMD64 2200, 1GB RAM
> > Software Environment: Gentoo
> > Problem Description: Ever since 2.6.17 my cd ripping speeds with one particular
> > CD ripper/encoder (namely the one I wrote) have been slow.
> >
> > Using git bisect I tracked it down to this patch..
> >
> > 9430d58e34ec3861e1ca72f8e49105b227aad327 is first bad commit
> > commit 9430d58e34ec3861e1ca72f8e49105b227aad327
> > Author: Mike Galbraith <efault@gmx.de>
> > Date: Wed Mar 22 00:07:33 2006 -0800
> >
> > [PATCH] sched: remove sleep_avg multiplier
> >
> > Remove the sleep_avg multiplier. This multiplier was necessary back when
> > we had 10 seconds of dynamic range in sleep_avg, but now that we only have
> > one second, it causes that one second to be compressed down to 100ms in
> > some cases. This is particularly noticeable when compiling a kernel in a
> > slow NFS mount, and I believe it to be a very likely candidate for other
> > recently reported network related interactivity problems.
> >
> > In testing, I can detect no negative impact of this removal.
> >
> > Signed-off-by: Mike Galbraith <efault@gmx.de>
> > Acked-by: Ingo Molnar <mingo@elte.hu>
> > Signed-off-by: Andrew Morton <akpm@osdl.org>
> > Signed-off-by: Linus Torvalds <torvalds@osdl.org>
> >
> > :040000 040000 28d2d8f53ab7b5dd89e846f2dcc107ce88cb695f 780a13c0f8ba5465db79c668
> >
> > I'm honestly not sure if my application is doing something it shouldn't or if
> > this is a legitimate kernel bug. Being totally at a loss I'm filing it here.I
> > just know that before the above patch I was ripping at about speeds of 9.0x and
> > now I rip at 1.2x.

It's pretty difficult imagining this patch being responsible for an IO
regression. The scheduling advantages for applications which sleep even
a little is still absolutely massive.

> sched problems...

I'm skeptical. Is the source for this application available? I'd like
to see this problem.

-Mike