From: Andi Kleen <ak@linux.intel.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Shaohua Li <shaohua.li@intel.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Hugh Dickins <hughd@google.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
David Miller <davem@davemloft.net>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
Russell King <rmk@arm.linux.org.uk>,
Paul Mundt <lethal@linux-sh.org>, Jeff Dike <jdike@addtoit.com>,
Richard Weinberger <richard@nod.at>,
"Luck, Tony" <tony.luck@intel.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Mel Gorman <mel@csn.ul.ie>, Nick Piggin <npiggin@kernel.dk>,
Namhyung Kim <namhyung@gmail.com>,
"Shi, Alex" <alex.shi@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"Rafael J. Wysocki" <rjw@sisk.pl>
Subject: Re: REGRESSION: Performance regressions from switching anon_vma->lock to mutex
Date: Wed, 15 Jun 2011 09:47:08 -0700 [thread overview]
Message-ID: <20110615164708.GB12162@tassilo.jf.intel.com> (raw)
In-Reply-To: <1308156337.2171.23.camel@laptop>
On Wed, Jun 15, 2011 at 06:45:37PM +0200, Peter Zijlstra wrote:
> On Wed, 2011-06-15 at 09:18 -0700, Andi Kleen wrote:
>
> > And in general it looks like blind conversion from spinlock to mutex
> > is a bad idea right now.
>
> For 4 socket machines, maybe. On 2 sockets I cannot reproduce anything.
With only one other guy active a lot of things are quite a bit easier.
Basically 2S is a trivial case here.
> I wonder if its the fairness thing, the mutex spinners aren't fifo fair
The Intel 4S systems are fair, but ticketing still helps significantly
because it has a lot nicer interconnect behaviour.
> like the ticket locks are. It could be significant with larger socket
> count since their cacheline arbitration is more sucky.
It gets a bit better with the patch I sent earlier to read the count
first, but yes it's a problem. However I'm not sure that even
with that fixed mutexes will be as good as plain ticket locks.
Also certainly it's no short term fix for 3.0. Right now
we still have this terrible regression.
-Andi
--
ak@linux.intel.com -- Speaking for myself only
next prev parent reply other threads:[~2011-06-15 16:48 UTC|newest]
Thread overview: 86+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-15 0:29 Tim Chen
2011-06-15 0:36 ` Andi Kleen
2011-06-17 19:07 ` Ingo Molnar
2011-06-15 1:21 ` Linus Torvalds
2011-06-15 3:42 ` Linus Torvalds
2011-06-15 1:26 ` Shaohua Li
2011-06-15 11:52 ` Peter Zijlstra
2011-06-15 12:49 ` Peter Zijlstra
2011-06-15 16:18 ` Andi Kleen
2011-06-15 16:45 ` Peter Zijlstra
2011-06-15 16:47 ` Andi Kleen [this message]
2011-06-15 18:43 ` Tim Chen
2011-06-15 20:32 ` Peter Zijlstra
2011-06-15 20:57 ` Andi Kleen
2011-06-15 21:12 ` Tim Chen
2011-06-15 21:37 ` Peter Zijlstra
2011-06-15 21:51 ` Linus Torvalds
2011-06-15 22:19 ` Andi Kleen
2011-06-16 0:16 ` Linus Torvalds
2011-06-16 20:14 ` Andi Kleen
2011-06-16 20:37 ` Linus Torvalds
2011-06-17 0:24 ` Andi Kleen
2011-06-17 9:13 ` Ingo Molnar
2011-06-15 22:15 ` Andi Kleen
2011-06-16 1:08 ` Tim Chen
2011-06-16 1:50 ` Linus Torvalds
2011-06-16 20:26 ` Tim Chen
2011-06-16 20:47 ` Linus Torvalds
2011-06-16 21:05 ` Linus Torvalds
2011-06-16 21:06 ` Linus Torvalds
2011-06-16 21:26 ` Linus Torvalds
2011-06-17 3:58 ` Linus Torvalds
2011-06-17 11:28 ` Peter Zijlstra
2011-06-17 11:54 ` Peter Zijlstra
2011-06-17 16:36 ` Linus Torvalds
2011-06-17 17:41 ` Hugh Dickins
2011-06-17 17:55 ` Peter Zijlstra
2011-06-17 18:01 ` Linus Torvalds
2011-06-17 18:18 ` Peter Zijlstra
2011-06-17 18:32 ` Peter Zijlstra
2011-06-17 18:39 ` Linus Torvalds
2011-06-17 18:41 ` Linus Torvalds
2011-06-17 20:19 ` Tim Chen
2011-06-17 22:20 ` Hugh Dickins
2011-06-18 4:47 ` Linus Torvalds
2011-06-17 19:53 ` [PATCH] mm, memory-failure: Fix spinlock vs mutex order Peter Zijlstra
2011-06-17 20:04 ` Andi Kleen
2011-06-17 16:46 ` REGRESSION: Performance regressions from switching anon_vma->lock to mutex Linus Torvalds
2011-06-17 17:28 ` Linus Torvalds
2011-06-17 19:40 ` Andi Kleen
2011-06-18 8:08 ` Ingo Molnar
2011-06-17 18:22 ` Tim Chen
2011-06-17 19:05 ` Ray Lee
2011-06-16 22:00 ` Andi Kleen
2011-06-15 10:36 ` Peter Zijlstra
2011-06-15 10:58 ` Peter Zijlstra
2011-06-15 11:41 ` Peter Zijlstra
2011-06-15 19:11 ` Linus Torvalds
2011-06-15 19:24 ` Andrew Morton
2011-06-15 20:16 ` Ingo Molnar
2011-06-15 20:55 ` Linus Torvalds
2011-06-15 20:12 ` [GIT PULL] " Ingo Molnar
2011-06-15 20:29 ` Paul E. McKenney
2011-06-15 20:47 ` Linus Torvalds
2011-06-15 20:54 ` Paul E. McKenney
2011-06-15 21:05 ` Linus Torvalds
2011-06-15 21:15 ` Paul E. McKenney
2011-06-15 21:27 ` Linus Torvalds
2011-06-16 7:03 ` Ingo Molnar
2011-06-16 17:16 ` Paul E. McKenney
2011-06-16 20:25 ` Ingo Molnar
2011-06-16 21:01 ` Frederic Weisbecker
2011-06-16 23:02 ` Ingo Molnar
2011-06-17 15:19 ` Frederic Weisbecker
2011-06-16 21:02 ` Andi Kleen
2011-06-16 22:21 ` Benjamin Herrenschmidt
2011-06-16 22:38 ` Ingo Molnar
2011-06-16 22:47 ` Andi Kleen
2011-06-16 22:58 ` Ingo Molnar
2011-06-17 0:45 ` Paul E. McKenney
2011-06-17 9:43 ` Ingo Molnar
2011-06-17 16:48 ` Paul E. McKenney
2011-06-16 23:37 ` Paul E. McKenney
2011-06-15 20:13 ` Tim Chen
2011-06-15 20:17 ` Ingo Molnar
2011-06-15 20:21 ` Tim Chen
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