From: Anton Blanchard <anton@samba.org>
To: Arnd Bergmann <arnd@arndb.de>
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>
Subject: Re: [PATCH] Yielding processor resources during lock contention
Date: Sun, 12 Sep 2004 20:43:06 +1000 [thread overview]
Message-ID: <20040912104306.GA25741@krispykreme> (raw)
In-Reply-To: <200409121210.32259.arnd@arndb.de>
Hi,
> For s390, this was solved by simply defining cpu_relax() to the hypervisor
> yield operation, because we found that cpu_relax() is used only in busy-wait
> situations where it makes sense to continue on another virtual CPU.
>
> What is the benefit of not always doing a full hypervisor yield when
> you hit cpu_relax()?
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.
Did you manage to see any improvement by yielding to the hypervisor
in cpu_relax?
Anton
next prev parent reply other threads:[~2004-09-12 10:47 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 [this message]
2004-09-12 11:12 ` Arnd Bergmann
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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