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From: Ingo Molnar <mingo@elte.hu>
To: Chris Mason <chris.mason@oracle.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Gregory Haskins <ghaskins@novell.com>,
	Matthew Wilcox <matthew@wil.cx>, Andi Kleen <andi@firstfloor.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	linux-btrfs <linux-btrfs@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Nick Piggin <npiggin@suse.de>,
	Peter Morreale <pmorreale@novell.com>,
	Sven Dietrich <SDietrich@novell.com>,
	Dmitry Adamushko <dmitry.adamushko@gmail.com>
Subject: Re: [PATCH -v9][RFC] mutex: implement adaptive spinning
Date: Wed, 14 Jan 2009 12:21:58 +0100	[thread overview]
Message-ID: <20090114112158.GA8625@elte.hu> (raw)
In-Reply-To: <1231901899.1709.18.camel@think.oraclecorp.com>


* Chris Mason <chris.mason@oracle.com> wrote:

> v10 is better that not spinning, but its in the 5-10% range.  So, I've 
> been trying to find ways to close the gap, just to understand exactly 
> where it is different.
> 
> If I take out:
> 	/*
> 	 * If there are pending waiters, join them.
> 	 */
> 	if (!list_empty(&lock->wait_list))
> 		break;
> 
> 
> v10 pops dbench 50 up to 1800MB/s.  The other tests soundly beat my 
> spinning and aren't less fair.  But clearly this isn't a good solution.

i think since we already decided that it's ok to be somewhat unfair (_all_ 
batching constructs introduce unfairness, so the question is never 'should 
we?' but 'by how much?'), we should just take this out and enjoy the speed 
...

	Ingo

  parent reply	other threads:[~2009-01-14 11:22 UTC|newest]

Thread overview: 92+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-01-12 15:37 [PATCH -v8][RFC] mutex: implement adaptive spinning Peter Zijlstra
2009-01-12 16:04 ` Linus Torvalds
2009-01-12 16:20   ` Linus Torvalds
2009-01-12 16:45     ` Chris Mason
2009-01-12 16:50       ` Peter Zijlstra
2009-01-12 17:14         ` Chris Mason
2009-01-12 17:24           ` Peter Zijlstra
2009-01-12 17:30             ` Chris Mason
2009-01-12 17:16     ` Peter Zijlstra
2009-01-12 17:33       ` Boaz Harrosh
2009-01-12 18:07         ` Peter Zijlstra
2009-01-12 16:13 ` Avi Kivity
2009-01-12 17:13   ` Peter Zijlstra
2009-01-12 17:23     ` Avi Kivity
2009-01-12 17:32     ` Avi Kivity
2009-01-14 16:46       ` Peter Zijlstra
2009-01-14 17:04         ` Nick Piggin
2009-01-14 17:23           ` Avi Kivity
2009-01-15  0:50             ` Nick Piggin
2009-01-13 15:15 ` [PATCH -v9][RFC] " Peter Zijlstra
2009-01-13 16:16   ` Linus Torvalds
2009-01-13 16:21     ` Peter Zijlstra
2009-01-13 16:39       ` Ingo Molnar
2009-01-13 16:40       ` Peter Zijlstra
2009-01-13 16:49         ` Linus Torvalds
2009-01-13 17:21           ` Peter Zijlstra
2009-01-13 18:33             ` Ingo Molnar
2009-01-13 18:40               ` Linus Torvalds
2009-01-13 19:01                 ` Ingo Molnar
2009-01-14  2:58             ` Chris Mason
2009-01-14 11:18               ` Dmitry Adamushko
2009-01-14 16:47                 ` Chris Mason
2009-01-14 17:32                   ` Dmitry Adamushko
2009-01-14 11:21               ` Ingo Molnar [this message]
2009-01-14 15:43                 ` Linus Torvalds
2009-01-14 16:23                   ` Chris Mason
2009-01-14 17:06                   ` [PATCH -v11 delta] " Ingo Molnar
2009-01-14 17:00             ` [PATCH -v11][RFC] " Peter Zijlstra
2009-01-14 17:18               ` Nick Piggin
2009-01-14 17:22                 ` Peter Zijlstra
2009-01-15  0:46                   ` Nick Piggin
2009-01-15  7:44                     ` Peter Zijlstra
2009-01-15  7:52                       ` Nick Piggin
2009-01-14 18:33               ` [GIT PULL] adaptive spinning mutexes Ingo Molnar
2009-01-14 18:40                 ` Chris Mason
2009-01-15  9:53                   ` Ingo Molnar
2009-01-14 18:47                 ` Ingo Molnar
2009-01-14 19:28                   ` Ingo Molnar
2009-01-15 17:44                     ` Matthew Wilcox
2009-01-15 18:05                       ` Linus Torvalds
2009-01-15 18:08                         ` Ingo Molnar
2009-01-15 18:16                           ` Linus Torvalds
2009-01-15 19:26                             ` Chris Mason
2009-01-15 20:13                               ` Linus Torvalds
2009-01-15 21:04                                 ` Chris Mason
2009-01-15 22:03                                   ` Ingo Molnar
2009-01-16 13:32                               ` Folkert van Heusden
2009-01-16 13:57                                 ` Folkert van Heusden
2009-01-16 18:37                               ` Bill Davidsen
2009-01-16  0:53                             ` Paul E. McKenney
2009-01-16  1:01                               ` Linus Torvalds
2009-01-16  1:34                                 ` Paul E. McKenney
2009-01-16 14:07                                 ` Folkert van Heusden
2009-01-16  3:03                             ` Nick Piggin
2009-01-15 18:06                       ` Ingo Molnar
2009-01-14 18:53                 ` Andrew Morton
2009-01-14 19:00                   ` Ingo Molnar
2009-01-14 19:36                     ` Andrew Morton
2009-01-14 19:50                       ` Peter Zijlstra
2009-01-14 20:21                         ` Andrew Morton
2009-01-14 20:27                         ` Ingo Molnar
2009-01-14 20:44                           ` Andrew Morton
2009-01-14 20:14                       ` Ingo Molnar
2009-01-14 20:30                         ` Andrew Morton
2009-01-14 20:51                           ` Ingo Molnar
2009-01-14 21:06                             ` Andrew Morton
2009-01-14 21:14                               ` Ingo Molnar
2009-01-14 21:35                                 ` Andrew Morton
2009-01-14 23:23                                   ` Ingo Molnar
2009-01-15  0:55                                   ` Nick Piggin
2009-01-14 21:41                                 ` Ingo Molnar
2009-01-14 21:50                                   ` Kay Sievers
2009-01-14 22:34                                     ` Ingo Molnar
2009-01-15 11:45                                       ` Folkert van Heusden
2009-01-15 12:53                                       ` Chris Samuel
2009-01-14 19:23                   ` Peter Zijlstra
2009-01-14 19:33                     ` Ingo Molnar
2009-01-15  8:41             ` [PATCH] mutex: set owner only once on acquisition Johannes Weiner
2009-01-15  8:56               ` Johannes Weiner
2009-01-13 18:12           ` [PATCH -v9][RFC] mutex: implement adaptive spinning Ingo Molnar
2009-01-13 18:21             ` Linus Torvalds
2009-01-13 18:24               ` Ingo Molnar

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