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From: Andrew Morton <akpm@linux-foundation.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	bugzilla-daemon@bugzilla.kernel.org,
	bugme-daemon@bugzilla.kernel.org, ant.starikov@gmail.com,
	Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [Bugme-new] [Bug 15618] New: 2.6.18->2.6.32->2.6.33 huge regression in performance
Date: Tue, 23 Mar 2010 11:13:51 -0700	[thread overview]
Message-ID: <20100323111351.756c8752.akpm@linux-foundation.org> (raw)
In-Reply-To: <20100323173409.GA24845@elte.hu>

On Tue, 23 Mar 2010 18:34:09 +0100
Ingo Molnar <mingo@elte.hu> wrote:

> 
> It shows a very brutal amount of page fault invoked mmap_sem spinning 
> overhead.
> 

Yes.  Note that we fall off a cliff at nine threads on a 16-way.  As
soon as a core gets two threads scheduled onto it?  Probably triggered
by an MM change, possibly triggered by a sched change which tickled a
preexisting MM shortcoming.  Who knows.

Anton, we have an executable binary in the bugzilla report but it would
be nice to also have at least a description of what that code is
actually doing.  A quick strace shows quite a lot of mprotect activity.
A pseudo-code walkthrough, perhaps?

Thanks.

WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	bugzilla-daemon@bugzilla.kernel.org,
	bugme-daemon@bugzilla.kernel.org, ant.starikov@gmail.com,
	Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [Bugme-new] [Bug 15618] New: 2.6.18->2.6.32->2.6.33 huge regression in performance
Date: Tue, 23 Mar 2010 11:13:51 -0700	[thread overview]
Message-ID: <20100323111351.756c8752.akpm@linux-foundation.org> (raw)
In-Reply-To: <20100323173409.GA24845@elte.hu>

On Tue, 23 Mar 2010 18:34:09 +0100
Ingo Molnar <mingo@elte.hu> wrote:

> 
> It shows a very brutal amount of page fault invoked mmap_sem spinning 
> overhead.
> 

Yes.  Note that we fall off a cliff at nine threads on a 16-way.  As
soon as a core gets two threads scheduled onto it?  Probably triggered
by an MM change, possibly triggered by a sched change which tickled a
preexisting MM shortcoming.  Who knows.

Anton, we have an executable binary in the bugzilla report but it would
be nice to also have at least a description of what that code is
actually doing.  A quick strace shows quite a lot of mprotect activity.
A pseudo-code walkthrough, perhaps?

Thanks.

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  parent reply	other threads:[~2010-03-23 18:14 UTC|newest]

Thread overview: 66+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <bug-15618-10286@https.bugzilla.kernel.org/>
2010-03-23 14:22 ` [Bugme-new] [Bug 15618] New: 2.6.18->2.6.32->2.6.33 huge regression in performance Andrew Morton
2010-03-23 14:22   ` Andrew Morton
2010-03-23 17:34   ` Ingo Molnar
2010-03-23 17:34     ` Ingo Molnar
2010-03-23 17:45     ` Linus Torvalds
2010-03-23 17:45       ` Linus Torvalds
2010-03-23 17:57       ` Anton Starikov
2010-03-23 17:57         ` Anton Starikov
2010-03-23 18:00       ` Ingo Molnar
2010-03-23 18:00         ` Ingo Molnar
2010-03-23 18:03         ` Anton Starikov
2010-03-23 18:03           ` Anton Starikov
2010-03-23 18:21           ` Andrew Morton
2010-03-23 18:21             ` Andrew Morton
2010-03-23 18:25             ` Anton Starikov
2010-03-23 18:25               ` Anton Starikov
2010-03-23 19:22               ` Robin Holt
2010-03-23 19:22                 ` Robin Holt
2010-03-23 19:30                 ` Anton Starikov
2010-03-23 19:30                   ` Anton Starikov
2010-03-23 19:49                   ` Robin Holt
2010-03-23 19:49                     ` Robin Holt
2010-03-23 19:57                     ` Robin Holt
2010-03-23 19:57                       ` Robin Holt
2010-03-23 19:50                 ` Anton Starikov
2010-03-23 19:50                   ` Anton Starikov
2010-03-23 19:52             ` Linus Torvalds
2010-03-23 19:52               ` Linus Torvalds
2010-03-24 16:40           ` Roland Dreier
2010-03-24 16:40             ` Roland Dreier
2010-03-26  3:24             ` Anton Starikov
2010-03-26  3:24               ` Anton Starikov
2010-03-23 19:14       ` Anton Starikov
2010-03-23 19:14         ` Anton Starikov
2010-03-23 19:17         ` Peter Zijlstra
2010-03-23 19:17           ` Peter Zijlstra
2010-03-23 19:42           ` Anton Starikov
2010-03-23 19:54         ` Linus Torvalds
2010-03-23 19:54           ` Linus Torvalds
2010-03-23 20:43           ` Anton Starikov
2010-03-23 20:43             ` Anton Starikov
2010-03-23 23:04             ` Linus Torvalds
2010-03-23 23:04               ` Linus Torvalds
2010-03-23 23:19               ` Anton Starikov
2010-03-23 23:19                 ` Anton Starikov
2010-03-23 23:36               ` Ingo Molnar
2010-03-23 23:36                 ` Ingo Molnar
2010-03-23 23:55                 ` Linus Torvalds
2010-03-23 23:55                   ` Linus Torvalds
2010-03-24  0:03                   ` Anton Starikov
2010-03-24  0:03                     ` Anton Starikov
2010-03-24  2:15                   ` Andi Kleen
2010-03-24  2:15                     ` Andi Kleen
2010-03-24  3:00                     ` Linus Torvalds
2010-03-24  3:00                       ` Linus Torvalds
2010-04-19 18:19                       ` Greg KH
2010-04-19 18:19                         ` Greg KH
2010-03-23 18:13     ` Andrew Morton [this message]
2010-03-23 18:13       ` Andrew Morton
2010-03-23 18:19       ` Anton Starikov
2010-03-23 18:19         ` Anton Starikov
2010-03-23 18:27       ` Ingo Molnar
2010-03-23 18:27         ` Ingo Molnar
2010-03-23 21:19       ` Anton Starikov
2010-03-23 21:19         ` Anton Starikov
2010-04-02 18:57   ` Lee Schermerhorn

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