Re: [Bug #12809] iozone regression with 2.6.29-rc6

Rafael J. Wysocki
2009-04-06T22:30:35Z

On Tuesday 07 April 2009, Wu Fengguang wrote:
> On Tue, Apr 07, 2009 at 06:15:09AM +0800, Wu Fengguang wrote:
> > On Tue, Apr 07, 2009 at 03:05:38AM +0800, Rafael J. Wysocki wrote:
> > > This message has been generated automatically as a part of a report
> > > of recent regressions.
> > >
> > > The following bug entry is on the current list of known regressions
> > > from 2.6.28. Please verify if it still should be listed and let me know
> > > (either way).
> > >
> > >
> > > Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=12809
> > > Subject : iozone regression with 2.6.29-rc6
> > > Submitter : Lin Ming <ming.m.lin@intel.com>
> > > Date : 2009-02-27 9:13 (39 days old)
> > > First-Bad-Commit: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=1cf6e7d83bf334cc5916137862c920a97aabc018
> > > References : http://marc.info/?l=linux-kernel&m=123572630504360&w=4
> > > http://lkml.org/lkml/2009/3/14/265
> > > Handled-By : Wu Fengguang <fengguang.wu@intel.com>
> > >
> >
> > This bug could be closed.
> >
> > The performance regression is triggered by commit 1cf6e7d83bf3(mm:
> > task dirty accounting fix). Which has been reverted in 2.6.29.
>
> Sorry for the mistake, commit 1cf6e7d83bf3 was _not_ reverted.
> So 2.6.29 is expected to have this regression..

Added -stable to the CC list. I'm not sure if that was included into .29.1.

> > For 2.6.30, commit 1cf6e7d83bf33(mm: task dirty accounting fix) and
> > 1b5e62b42b55(writeback: double the dirty thresholds) were just merged
> > together. The latter one restores the iozone performance. (However
> > might deteriorate some writeback slowness bugs..)

Thanks, I've closed the bug.

Rafael