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From: Arnd Bergmann <arnd@arndb.de>
To: Anton Blanchard <anton@samba.org>
Cc: Zwane Mwaikambo <zwane@fsmlabs.com>,
	Linus Torvalds <torvalds@osdl.org>,
	Paul Mackerras <paulus@samba.org>,
	Linux Kernel <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@osdl.org>,
	"Nakajima, Jun" <jun.nakajima@intel.com>, Andi Kleen <ak@suse.de>,
	Ingo Molnar <mingo@elte.hu>,
	Martin Schwidefsky <schwidefsky@de.ibm.com>,
	Eberhard Pasch <epasch@de.ibm.com>
Subject: Re: [PATCH] Yielding processor resources during lock contention
Date: Sun, 12 Sep 2004 13:12:17 +0200	[thread overview]
Message-ID: <200409121312.21358.arnd@arndb.de> (raw)
In-Reply-To: <20040912104306.GA25741@krispykreme>

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On Sonntag, 12. September 2004 12:43, Anton Blanchard wrote:
> cpu_relax doesnt tell us why we are busy looping. In this particular
> case we want to pass to the hypervisor which virtual cpu we are waiting
> on so the hypervisor make better scheduling decisions.

Ah, interesting. I think s390 could do the same with the upcoming 5.1 release
of z/VM. However, we decided to ask for an implementation of a futex hypercall
instead, which lets us implement the linux spinlock as a hypervisor semaphore.

> Did you manage to see any improvement by yielding to the hypervisor
> in cpu_relax?
I'm not sure if this has been measured, maybe Martin or Eberhard knows more.

	Arnd <><

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  reply	other threads:[~2004-09-12 11:13 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-09-03  0:02 [PATCH][5/8] Arch agnostic completely out of line locks / ppc64 Zwane Mwaikambo
2004-09-09  5:42 ` Paul Mackerras
2004-09-09 12:41   ` Zwane Mwaikambo
2004-09-09 14:54     ` Linus Torvalds
2004-09-09 14:55       ` Linus Torvalds
2004-09-09 15:32         ` Zwane Mwaikambo
2004-09-12  4:59           ` [PATCH] Yielding processor resources during lock contention Zwane Mwaikambo
2004-09-12  5:00             ` Andrew Morton
2004-09-12  5:10               ` Anton Blanchard
2004-09-12  5:13               ` Zwane Mwaikambo
2004-09-12  4:32                 ` Nick Piggin
2004-09-12  5:33                   ` Zwane Mwaikambo
2004-09-12  4:46                     ` Nick Piggin
2004-09-12  5:51                       ` Zwane Mwaikambo
2004-09-12  5:02                         ` Nick Piggin
2004-09-12  6:09                           ` Anton Blanchard
2004-09-12  6:58                             ` William Lee Irwin III
2004-09-12  5:18                 ` Andrew Morton
2004-09-12  5:10             ` Linus Torvalds
2004-09-12  5:27               ` Zwane Mwaikambo
2004-09-13 12:21                 ` [PATCH] Yielding processor resources during lock contention #2 Zwane Mwaikambo
2004-09-12  7:49             ` [PATCH] Yielding processor resources during lock contention Ingo Molnar
2004-09-12 16:10               ` Zwane Mwaikambo
2004-09-12 19:34                 ` Ingo Molnar
2004-09-12 10:10             ` Arnd Bergmann
2004-09-12 10:43               ` Anton Blanchard
2004-09-12 11:12                 ` Arnd Bergmann [this message]
2004-09-09 15:43     ` [PATCH][5/8] Arch agnostic completely out of line locks / ppc64 Anton Blanchard
2004-09-09 17:19       ` William Lee Irwin III
2004-09-09 21:38         ` Paul Mackerras
2004-09-09 22:00           ` William Lee Irwin III
2004-09-09 23:36             ` Paul Mackerras
2004-09-10  0:09               ` William Lee Irwin III
2004-09-10  0:21                 ` Linus Torvalds
2004-09-10  0:35                   ` Anton Blanchard
2004-09-10  0:54                     ` Linus Torvalds
2004-09-10  1:42                       ` Anton Blanchard
2004-09-10  1:50                         ` Anton Blanchard
2004-09-10  2:22                           ` William Lee Irwin III
2004-09-10  2:32                             ` William Lee Irwin III
2004-09-10  2:37                               ` William Lee Irwin III
2004-09-10  3:24                             ` Anton Blanchard
2004-09-10  7:40                             ` Ingo Molnar
2004-09-10 12:16                               ` William Lee Irwin III
2004-09-10 12:22                                 ` Ingo Molnar
2004-09-10  3:23                       ` Anton Blanchard
2004-09-10  7:56                         ` Anton Blanchard
  -- strict thread matches above, loose matches on Subject: below --
2004-09-13  0:45 [PATCH] Yielding processor resources during lock contention Nakajima, Jun
2004-09-13  1:35 Nakajima, Jun
2004-09-13  6:35 ` Ingo Molnar

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