From: Andi Kleen <ak@suse.de>
To: Kirill Korotaev <dev@sw.ru>
Cc: linux-kernel@vger.kernel.org, Linus Torvalds <torvalds@osdl.org>,
Andrew Morton <akpm@osdl.org>,
xemul@sw.ru, "Andrey Savochkin" <saw@sawoct.com>,
st@sw.ru, discuss@x86-64.org
Subject: Re: SMP syncronization on AMD processors (broken?)
Date: 06 Oct 2005 15:32:30 +0200 [thread overview]
Message-ID: <p73hdbuzs7l.fsf@verdi.suse.de> (raw)
In-Reply-To: <434520FF.8050100@sw.ru>
Kirill Korotaev <dev@sw.ru> writes:
> Please help with a not simple question about spin_lock/spin_unlock on
> SMP archs. The question is whether concurrent spin_lock()'s should
> acquire it in more or less "fair" fashinon or one of CPUs can starve
> any arbitrary time while others do reacquire it in a loop.
They are not fully fair because of the NUMAness of the system.
Same on many other NUMA systems.
We considered long ago to use queued locks to avoid this, but
they are quite costly for the uncongested case and never seemed worth it.
So live with it.
-Andi
next prev parent reply other threads:[~2005-10-06 13:32 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-10-06 13:05 SMP syncronization on AMD processors (broken?) Kirill Korotaev
2005-10-06 13:14 ` linux-os (Dick Johnson)
2005-10-06 13:19 ` Arjan van de Ven
2005-10-06 13:32 ` Andrey Savochkin
2005-10-06 14:22 ` Arjan van de Ven
2005-10-06 13:32 ` Andi Kleen [this message]
2005-10-06 13:46 ` Andrey Savochkin
2005-10-06 14:02 ` [discuss] " Andi Kleen
2005-10-06 14:52 ` Linus Torvalds
2005-10-06 15:21 ` Andrey Savochkin
2005-10-06 15:46 ` Linus Torvalds
2005-10-11 0:59 ` Andrew Morton
2005-10-11 1:20 ` Andi Kleen
2005-10-11 3:20 ` Joe Seigh
2005-10-06 13:50 ` Eric Dumazet
2005-10-06 13:56 ` [discuss] " Andi Kleen
2005-10-06 14:10 ` Eric Dumazet
2005-10-06 14:11 ` Andi Kleen
2005-10-06 14:45 ` Linus Torvalds
2005-10-06 15:34 ` Hugh Dickins
2005-10-06 15:53 ` Eric Dumazet
2005-10-06 16:01 ` Linus Torvalds
2005-10-07 20:38 ` Joe Seigh
2005-10-07 20:57 ` Stephen Hemminger
2005-10-13 18:24 ` Joe Seigh
-- strict thread matches above, loose matches on Subject: below --
2005-10-08 9:31 Chuck Ebbert
2005-10-11 23:50 linux
2005-10-12 2:12 ` Christopher Friesen
2005-10-12 2:39 ` linux
2005-10-12 3:27 ` Kyle Moffett
2005-10-13 12:25 ` Kirill Korotaev
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