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From: Ingo Molnar <mingo@elte.hu>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andi Kleen <andi@firstfloor.org>, Matthew Wilcox <matthew@wil.cx>,
	"Zhang, Yanmin" <yanmin_zhang@linux.intel.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Alexander Viro <viro@ftp.linux.org.uk>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: AIM7 40% regression with 2.6.26-rc1
Date: Wed, 7 May 2008 18:20:12 +0200	[thread overview]
Message-ID: <20080507162012.GA10096@elte.hu> (raw)
In-Reply-To: <alpine.LFD.1.10.0805070728280.32269@woody.linux-foundation.org>


* Linus Torvalds <torvalds@linux-foundation.org> wrote:

> I think turning the BKL into a semaphore was fine per se, but that was 
> when semaphores were fast.

hm, do we know it for a fact that the 40% AIM regression is due to the 
fastpath overhead of the BKL? It would be extraordinary if so.

I think it is far more likely that it's due to the different scheduling 
and wakeup behavior of the new kernel/semaphore.c code. So the fix would 
be to restore the old scheduling behavior - that's what Yanmin's manual 
revert did and that's what got him back the previous AIM7 performance.

	Ingo

  parent reply	other threads:[~2008-05-07 16:20 UTC|newest]

Thread overview: 140+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-05-06  5:48 AIM7 40% regression with 2.6.26-rc1 Zhang, Yanmin
2008-05-06 11:18 ` Matthew Wilcox
2008-05-06 11:44 ` Ingo Molnar
2008-05-06 12:09   ` Matthew Wilcox
2008-05-06 16:23     ` Matthew Wilcox
2008-05-06 16:36       ` Linus Torvalds
2008-05-06 16:42         ` Matthew Wilcox
2008-05-06 16:39           ` Alan Cox
2008-05-06 16:51             ` Matthew Wilcox
2008-05-06 16:45               ` Alan Cox
2008-05-06 17:42               ` Linus Torvalds
2008-05-06 20:28           ` Linus Torvalds
2008-05-06 16:44         ` J. Bruce Fields
2008-05-06 17:21       ` Andrew Morton
2008-05-06 17:31         ` Matthew Wilcox
2008-05-06 17:49           ` Ingo Molnar
2008-05-06 18:07             ` Andrew Morton
2008-05-11 11:11               ` Matthew Wilcox
2008-05-06 17:39         ` Ingo Molnar
2008-05-07  6:49           ` Zhang, Yanmin
2008-05-06 17:45         ` Linus Torvalds
2008-05-07 16:38         ` Matthew Wilcox
2008-05-07 16:55           ` Linus Torvalds
2008-05-07 17:08             ` Linus Torvalds
2008-05-07 17:16               ` Andrew Morton
2008-05-07 17:27                 ` Linus Torvalds
2008-05-07 17:22               ` Ingo Molnar
2008-05-07 17:25                 ` Ingo Molnar
2008-05-07 17:31                 ` Linus Torvalds
2008-05-07 17:47                   ` Linus Torvalds
2008-05-07 17:49                   ` Ingo Molnar
2008-05-07 18:02                     ` Linus Torvalds
2008-05-07 18:17                       ` Ingo Molnar
2008-05-07 18:27                         ` Linus Torvalds
2008-05-07 18:43                           ` Ingo Molnar
2008-05-07 19:01                             ` Linus Torvalds
2008-05-07 19:09                               ` Ingo Molnar
2008-05-07 19:24                               ` Matthew Wilcox
2008-05-07 19:44                                 ` Linus Torvalds
2008-05-07 20:00                                   ` Oi. NFS people. Read this Matthew Wilcox
2008-05-07 22:10                                     ` Trond Myklebust
2008-05-09  1:43                                       ` J. Bruce Fields
2008-05-08  3:24       ` AIM7 40% regression with 2.6.26-rc1 Zhang, Yanmin
2008-05-08  3:34         ` Linus Torvalds
2008-05-08  4:37           ` Zhang, Yanmin
2008-05-08 14:58             ` Linus Torvalds
2008-05-07  2:11   ` Zhang, Yanmin
2008-05-07  3:41     ` Zhang, Yanmin
2008-05-07  3:59       ` Andrew Morton
2008-05-07  4:46         ` Zhang, Yanmin
2008-05-07  6:26       ` Ingo Molnar
2008-05-07  6:28         ` Ingo Molnar
2008-05-07  7:05           ` Zhang, Yanmin
2008-05-07 11:00       ` Andi Kleen
2008-05-07 11:46         ` Matthew Wilcox
2008-05-07 12:21           ` Andi Kleen
2008-05-07 14:36             ` Linus Torvalds
2008-05-07 14:35               ` Alan Cox
2008-05-07 15:00                 ` Linus Torvalds
2008-05-07 15:02                   ` Linus Torvalds
2008-05-07 14:57               ` Andi Kleen
2008-05-07 15:31                 ` Andrew Morton
2008-05-07 16:22                   ` Matthew Wilcox
2008-05-07 15:19               ` Linus Torvalds
2008-05-07 17:14                 ` Ingo Molnar
2008-05-08  2:44                 ` Zhang, Yanmin
2008-05-08  3:29                   ` Linus Torvalds
2008-05-08  4:08                     ` Zhang, Yanmin
2008-05-08  4:17                       ` Linus Torvalds
2008-05-08 12:01                         ` [patch] speed up / fix the new generic semaphore code (fix AIM7 40% regression with 2.6.26-rc1) Ingo Molnar
2008-05-08 12:28                           ` Ingo Molnar
2008-05-08 14:43                             ` Ingo Molnar
2008-05-08 15:10                               ` [git pull] scheduler fixes Ingo Molnar
2008-05-08 15:33                                 ` Adrian Bunk
2008-05-08 15:41                                   ` Ingo Molnar
2008-05-08 19:42                                     ` Adrian Bunk
2008-05-11 11:03                                 ` Matthew Wilcox
2008-05-11 11:14                                   ` Matthew Wilcox
2008-05-11 11:48                                   ` Matthew Wilcox
2008-05-11 12:50                                     ` Ingo Molnar
2008-05-11 12:52                                       ` Ingo Molnar
2008-05-11 13:02                                         ` Matthew Wilcox
2008-05-11 13:26                                           ` Matthew Wilcox
2008-05-11 14:00                                             ` Ingo Molnar
2008-05-11 14:18                                               ` Matthew Wilcox
2008-05-11 14:42                                                 ` Ingo Molnar
2008-05-11 14:48                                                   ` Matthew Wilcox
2008-05-11 15:19                                                     ` Ingo Molnar
2008-05-11 15:29                                                       ` Matthew Wilcox
2008-05-13 14:11                                                         ` Ingo Molnar
2008-05-13 14:21                                                           ` Matthew Wilcox
2008-05-13 14:42                                                             ` Ingo Molnar
2008-05-13 15:28                                                               ` Matthew Wilcox
2008-05-13 17:13                                                                 ` Ingo Molnar
2008-05-13 17:22                                                                   ` Linus Torvalds
2008-05-13 21:05                                                                     ` Ingo Molnar
2008-05-11 13:54                                           ` Ingo Molnar
2008-05-11 14:22                                             ` Matthew Wilcox
2008-05-11 14:32                                               ` Ingo Molnar
2008-05-11 14:46                                                 ` Matthew Wilcox
2008-05-11 16:47                                                 ` Linus Torvalds
2008-05-11 13:01                                   ` Ingo Molnar
2008-05-11 13:06                                     ` Matthew Wilcox
2008-05-11 13:45                                       ` Ingo Molnar
2008-05-11 14:10                                   ` Sven Wegener
2008-05-08 16:02                             ` [patch] speed up / fix the new generic semaphore code (fix AIM7 40% regression with 2.6.26-rc1) Linus Torvalds
2008-05-08 18:30                               ` Linus Torvalds
2008-05-08 20:19                                 ` Ingo Molnar
2008-05-08 20:27                                   ` Linus Torvalds
2008-05-08 21:45                                     ` Ingo Molnar
2008-05-08 22:02                                       ` Ingo Molnar
2008-05-08 22:55                                       ` Linus Torvalds
2008-05-08 23:07                                         ` Linus Torvalds
2008-05-08 23:14                                           ` Linus Torvalds
2008-05-08 23:16                                         ` Alan Cox
2008-05-08 23:33                                           ` Linus Torvalds
2008-05-08 23:27                                             ` Alan Cox
2008-05-09  6:50                                             ` Ingo Molnar
2008-05-09  8:29                                             ` Andi Kleen
2008-05-08 13:20                           ` Matthew Wilcox
2008-05-08 15:01                             ` Ingo Molnar
2008-05-08 13:56                           ` Arjan van de Ven
2008-05-08  6:43                   ` AIM7 40% regression with 2.6.26-rc1 Ingo Molnar
2008-05-08  6:48                     ` Andrew Morton
2008-05-08  7:14                     ` Zhang, Yanmin
2008-05-08  7:39                       ` Ingo Molnar
2008-05-08  8:44                         ` Zhang, Yanmin
2008-05-08  9:21                           ` Ingo Molnar
2008-05-08  9:29                             ` Ingo Molnar
2008-05-08  9:30                             ` Zhang, Yanmin
2008-05-07 16:20               ` Ingo Molnar [this message]
2008-05-07 16:35                 ` Linus Torvalds
2008-05-07 17:05                   ` Ingo Molnar
2008-05-07 17:24                     ` Linus Torvalds
2008-05-07 17:36                       ` Ingo Molnar
2008-05-07 17:55                         ` Linus Torvalds
2008-05-07 17:59                           ` Matthew Wilcox
2008-05-07 18:17                             ` Linus Torvalds
2008-05-07 18:49                               ` Ingo Molnar
2008-05-07 13:59         ` Alan Cox

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