Subject : iozone regression with 2.6.29-rc6 Submitter : Lin Ming <ming.m.lin@intel.com> Date : 2009-02-27 9:13 References : http://marc.info/?l=linux-kernel&m=123572630504360&w=4 Handled-By : Wu Fengguang <fengguang.wu@intel.com> This entry is being used for tracking a regression from 2.6.28. Please don't close it until the problem is fixed in the mainline. Caused by: commit 1cf6e7d83bf334cc5916137862c920a97aabc018 Author: Nick Piggin <npiggin@suse.de> Date: Wed Feb 18 14:48:18 2009 -0800 mm: task dirty accounting fix Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Signed-off-by: Nick Piggin <npiggin@suse.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
First-Bad-Commit : 1cf6e7d83bf334cc5916137862c920a97aabc018
On Thursday 05 March 2009, Wu Fengguang wrote: > On Tue, Mar 03, 2009 at 09:25:59PM +0200, 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 (5 days old) > > Following Peter's idea of relaxing writeback throttling, Lin Ming > and I tried the idea of totally disabling writeback throttling by > doing benchmarks with the following parameters: > > echo 60 > /proc/sys/vm/dirty_ratio > echo 50 > /proc/sys/vm/dirty_background_ratio > > The result is encouraging: the iozone performance is restored to the > level of 2.6.29-rc5! > > We'll continue to evaluate the dirty/throttling numbers with Nick's patch.
References : http://lkml.org/lkml/2009/3/14/265
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.. > > > 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..)