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

[Mike Galbraith <efault@gmx.de>]

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

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