From: Russell King <rmk+lkml@arm.linux.org.uk>
To: "Yu, Fenghua" <fenghua.yu@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Ravikiran G Thirumalai <kiran@scalex86.org>,
"Siddha, Suresh B" <suresh.b.siddha@intel.com>,
clameter@sgi.com, linux-kernel@vger.kernel.org,
schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com
Subject: Re: [PATCH 1/2] Define new percpu interface for shared data -- version 3
Date: Fri, 25 May 2007 10:43:24 +0100 [thread overview]
Message-ID: <20070525094323.GB20090@flint.arm.linux.org.uk> (raw)
In-Reply-To: <79E93560F4A5FD42BB769DAAF8BEF62A01AA8E7C@scsmsx411.amr.corp.intel.com>
On Wed, May 23, 2007 at 02:13:24PM -0700, Yu, Fenghua wrote:
> Yes, in theory, sharing shared percpu data with local percpu data in one
> cache line can cause cache line contention between remote and local
> access.
What's "shared percpu data" ? It sounds to me like a contradiction in
terms. Isn't percpu data supposed to only be accessed by the CPU which
owns it to prevent cache line bouncing? In which case, what's the point
of sharing that data with other CPUs? Surely "shared percpu data" is
just the same as normal data?
--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of:
next prev parent reply other threads:[~2007-05-25 9:43 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-05-22 12:47 is TIF_NOTIFY_RESUME used? Stephane Eranian
2007-05-22 16:02 ` Andrew Morton
2007-05-22 16:07 ` Stephane Eranian
2007-05-22 16:15 ` Andrew Morton
2007-05-22 22:51 ` Stephane Eranian
2007-05-22 23:02 ` Andrew Morton
2007-05-23 9:57 ` [PATCH] remove unused TIF_NOTIFY_RESUME flag Stephane Eranian
2007-05-22 18:20 ` [PATCH 1/2] Define new percpu interface for shared data -- version 3 Fenghua Yu
2007-05-23 17:49 ` Andrew Morton
2007-05-23 18:26 ` Yu, Fenghua
2007-05-23 18:57 ` Ravikiran G Thirumalai
2007-05-23 19:09 ` Yu, Fenghua
2007-05-23 19:20 ` Ravikiran G Thirumalai
2007-05-23 19:31 ` Andrew Morton
2007-05-23 21:13 ` Yu, Fenghua
2007-05-25 9:43 ` Russell King [this message]
2007-05-25 15:24 ` Yu, Fenghua
2007-05-24 9:03 ` Martin Schwidefsky
2007-05-24 10:16 ` Ravikiran G Thirumalai
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