From: Andi Kleen <ak@muc.de>
To: suparna@in.ibm.com
Cc: Andrew Morton <akpm@osdl.org>,
Badari Pulavarty <pbadari@us.ibm.com>,
linux-aio@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: aio stress panic on 2.6.11-mm1
Date: Wed, 09 Mar 2005 12:11:26 +0100 [thread overview]
Message-ID: <m1oedtvztt.fsf@muc.de> (raw)
In-Reply-To: <20050309110404.GA4088@in.ibm.com> (Suparna Bhattacharya's message of "Wed, 9 Mar 2005 16:34:04 +0530")
Suparna Bhattacharya <suparna@in.ibm.com> writes:
> Any sense of how costly it is to use spin_lock_irq's vs spin_lock
> (across different architectures) ? Isn't rwsem used very widely ?
On P4s cli/sti is quite costly, let's says 100+ cycles. That is mostly
because it synchronizes the CPU partly. The Intel tables say 26/36 cycles
latency, but in practice it seems to take longer because of the
synchronization.
I would assume this is the worst case, everywhere else it should
be cheaper (except perhaps in some virtualized environments)
On P-M and AMD K7/K8 it is only a few cycles difference.
-Andi
prev parent reply other threads:[~2005-03-09 11:14 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20050308170107.231a145c.akpm@osdl.org>
[not found] ` <1110327267.24286.139.camel@dyn318077bld.beaverton.ibm.com>
[not found] ` <18744.1110364438@redhat.com>
2005-03-09 11:04 ` aio stress panic on 2.6.11-mm1 Suparna Bhattacharya
2005-03-09 11:05 ` Andrew Morton
2005-03-09 11:07 ` Arjan van de Ven
2005-03-09 11:17 ` Andi Kleen
2005-03-09 11:28 ` Andrew Morton
2005-03-09 11:59 ` David Howells
2005-03-09 12:12 ` [PATCH] rwsem: Make rwsems use interrupt disabling spinlocks David Howells
2005-03-09 17:35 ` Badari Pulavarty
2005-03-09 19:18 ` Badari Pulavarty
2005-03-09 19:16 ` Badari Pulavarty
2005-03-09 19:42 ` Andrew Morton
2005-03-09 20:10 ` Arjan van de Ven
2005-03-11 9:40 ` Ingo Molnar
2005-03-11 10:07 ` Andrew Morton
2005-03-11 10:25 ` Ingo Molnar
2005-03-09 11:10 ` aio stress panic on 2.6.11-mm1 Arjan van de Ven
2005-03-09 11:21 ` Andi Kleen
2005-03-09 14:48 ` Suparna Bhattacharya
2005-03-09 21:58 ` David Howells
2005-03-09 11:11 ` Andi Kleen [this message]
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