From: Mel Gorman <mgorman@suse.de>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>,
Nikolay Ulyanitsky <lystor@gmail.com>,
Mike Galbraith <efault@gmx.de>,
linux-kernel@vger.kernel.org,
Andreas Herrmann <andreas.herrmann3@amd.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>
Subject: Re: 20% performance drop on PostgreSQL 9.2 from kernel 3.5.3 to 3.6-rc5 on AMD chipsets - bisected
Date: Mon, 24 Sep 2012 16:00:48 +0100 [thread overview]
Message-ID: <20120924150048.GB11266@suse.de> (raw)
In-Reply-To: <CA+55aFwn3UhTDDch4+-=9=T3rHpDvqphY+NLtf2Ljq-7eG+gYw@mail.gmail.com>
On Fri, Sep 14, 2012 at 02:42:44PM -0700, Linus Torvalds wrote:
> On Fri, Sep 14, 2012 at 2:27 PM, Borislav Petkov <bp@alien8.de> wrote:
> >
> > as Nikolay says below, we have a regression in 3.6 with pgbench's
> > benchmark in postgresql.
> >
> > I was able to reproduce it on another box here and did a bisection run.
> > It pointed to the commit below.
>
> Ok. I guess we should just revert it. However, before we do that,
> maybe Mike can make it just use the exact old semantics of
> select_idle_sibling() in the update_top_cache_domain() logic.
>
The patch that you being reverted was meant to fix problems with
commit 4dcfe102 (sched: Avoid SMT siblings in select_idle_sibling() if
possible). That patch made select_idle_sibling() quite fat and I know it
is responsible for a 2% regression in a kernel compile benchmark between
kernel 3.1 and 3.2 on an old AMD Phenom II X4 940. Reverting Mike's patch
might fix this Postgres regression but it reintroduces the overhead caused
by commit 4dcfe102 for other cases. I do not have a suggestion on how to
make this better, I'm just pointing out that the revert has some downsides.
--
Mel Gorman
SUSE Labs
next prev parent reply other threads:[~2012-09-24 15:00 UTC|newest]
Thread overview: 115+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-14 7:47 20% performance drop on PostgreSQL 9.2 from kernel 3.5.3 to 3.6-rc5 on AMD chipsets Nikolay Ulyanitsky
2012-09-14 18:40 ` Borislav Petkov
2012-09-14 18:51 ` Borislav Petkov
2012-09-14 21:27 ` 20% performance drop on PostgreSQL 9.2 from kernel 3.5.3 to 3.6-rc5 on AMD chipsets - bisected Borislav Petkov
2012-09-14 21:40 ` Peter Zijlstra
2012-09-14 21:44 ` Linus Torvalds
2012-09-14 21:56 ` Peter Zijlstra
2012-09-14 21:59 ` Peter Zijlstra
2012-09-15 3:57 ` Mike Galbraith
2012-09-14 22:01 ` Linus Torvalds
2012-09-14 22:10 ` Peter Zijlstra
2012-09-14 22:20 ` Linus Torvalds
2012-09-14 22:14 ` Borislav Petkov
2012-09-14 21:45 ` Borislav Petkov
2012-09-14 21:42 ` Linus Torvalds
2012-09-15 3:33 ` Mike Galbraith
2012-09-15 16:16 ` Andi Kleen
2012-09-15 16:36 ` Mike Galbraith
2012-09-15 17:08 ` richard -rw- weinberger
2012-09-16 4:48 ` Mike Galbraith
2012-09-15 21:32 ` Alan Cox
2012-09-16 4:35 ` Mike Galbraith
2012-09-16 19:57 ` Linus Torvalds
2012-09-17 8:08 ` Mike Galbraith
2012-09-17 10:07 ` Ingo Molnar
2012-09-17 10:47 ` Mike Galbraith
2012-09-17 14:39 ` Andi Kleen
2012-09-19 12:35 ` Mike Galbraith
2012-09-19 14:54 ` Ingo Molnar
2012-09-19 15:23 ` Mike Galbraith
2012-09-24 15:00 ` Mel Gorman [this message]
2012-09-24 15:23 ` Nikolay Ulyanitsky
2012-09-24 15:53 ` Borislav Petkov
2012-09-24 15:30 ` Peter Zijlstra
2012-09-24 15:51 ` Mike Galbraith
2012-09-24 15:52 ` Linus Torvalds
2012-09-24 16:07 ` Peter Zijlstra
2012-09-24 16:33 ` Linus Torvalds
2012-09-24 16:54 ` Peter Zijlstra
2012-09-25 12:10 ` Hillf Danton
2012-09-24 16:12 ` Peter Zijlstra
2012-09-24 16:30 ` Linus Torvalds
2012-09-24 16:52 ` Borislav Petkov
2012-09-24 16:54 ` Peter Zijlstra
2012-09-24 17:44 ` Peter Zijlstra
2012-09-25 13:23 ` Mel Gorman
2012-09-25 14:36 ` Peter Zijlstra
2012-09-24 18:26 ` Mike Galbraith
2012-09-24 19:12 ` Linus Torvalds
2012-09-24 19:20 ` Borislav Petkov
2012-09-25 1:57 ` Mike Galbraith
2012-09-25 2:11 ` Linus Torvalds
2012-09-25 2:49 ` Mike Galbraith
2012-09-25 3:10 ` Linus Torvalds
2012-09-25 3:20 ` Mike Galbraith
2012-09-25 3:32 ` Linus Torvalds
2012-09-25 3:43 ` Mike Galbraith
2012-09-25 11:58 ` Peter Zijlstra
2012-09-25 13:17 ` Borislav Petkov
2012-09-25 17:00 ` Borislav Petkov
2012-09-25 17:21 ` Linus Torvalds
2012-09-25 18:42 ` Borislav Petkov
2012-09-25 19:08 ` Linus Torvalds
2012-09-26 2:23 ` Mike Galbraith
2012-09-26 17:17 ` Borislav Petkov
2012-09-26 2:00 ` Mike Galbraith
2012-09-26 2:22 ` Linus Torvalds
2012-09-26 2:42 ` Mike Galbraith
2012-09-26 17:15 ` Borislav Petkov
2012-09-26 16:32 ` Borislav Petkov
2012-09-26 18:19 ` Linus Torvalds
2012-09-26 21:37 ` Borislav Petkov
2012-09-27 5:09 ` Mike Galbraith
2012-09-27 5:18 ` Borislav Petkov
2012-09-27 5:44 ` Mike Galbraith
2012-09-27 5:47 ` Ingo Molnar
2012-09-27 5:59 ` Ingo Molnar
2012-09-27 6:34 ` Mike Galbraith
2012-09-27 6:41 ` Ingo Molnar
2012-09-27 6:54 ` Mike Galbraith
2012-09-27 7:10 ` Ingo Molnar
2012-09-27 16:25 ` Borislav Petkov
2012-09-27 17:44 ` Linus Torvalds
2012-09-27 18:05 ` Borislav Petkov
2012-09-27 18:19 ` Linus Torvalds
2012-09-27 18:29 ` Peter Zijlstra
2012-09-27 19:24 ` Borislav Petkov
2012-09-28 3:50 ` Mike Galbraith
2012-09-28 12:30 ` Borislav Petkov
2012-09-27 19:40 ` Linus Torvalds
2012-09-28 4:13 ` Mike Galbraith
2012-09-28 8:37 ` Peter Zijlstra
2012-09-27 7:17 ` david
2012-09-27 7:55 ` Mike Galbraith
2012-09-27 10:20 ` Borislav Petkov
2012-09-27 13:38 ` Mike Galbraith
2012-09-27 16:55 ` david
2012-09-27 4:32 ` Mike Galbraith
2012-09-27 8:21 ` Peter Zijlstra
2012-09-27 16:48 ` david
2012-09-27 17:38 ` Peter Zijlstra
2012-09-27 17:45 ` david
2012-09-27 18:09 ` Peter Zijlstra
2012-09-27 18:15 ` Linus Torvalds
2012-09-27 18:24 ` Borislav Petkov
2012-09-25 1:39 ` Mike Galbraith
2012-09-25 21:11 ` Suresh Siddha
2012-09-25 4:16 ` Mike Galbraith
2012-09-15 4:11 ` Mike Galbraith
[not found] ` <CA+55aFz1A7HbMYS9o-GTS5Zm=Xx8MUD7cR05GMVo--2E34jcgQ@mail.gmail.com>
2012-09-15 4:42 ` Mike Galbraith
2012-09-15 10:44 ` Borislav Petkov
2012-09-15 14:47 ` Mike Galbraith
2012-09-15 15:18 ` Borislav Petkov
2012-09-15 16:13 ` Mike Galbraith
2012-09-15 19:44 ` Borislav Petkov
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