From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Andi Kleen <ak@suse.de>
Cc: linux-arch@vger.kernel.org, Linus Torvalds <torvalds@osdl.org>,
Andrew Morton <akpm@osdl.org>
Subject: Re: [patch] make spin_lock_prefetch a noop for UP
Date: Thu, 04 Aug 2005 23:16:22 +1000 [thread overview]
Message-ID: <42F21526.90700@yahoo.com.au> (raw)
In-Reply-To: <20050804131037.GC9112@wotan.suse.de>
Andi Kleen wrote:
> On Thu, Aug 04, 2005 at 11:07:00PM +1000, Nick Piggin wrote:
>
>>Is this any good?
>>
>>The counter argument would be that one might prefetch a
>>spinlock in the head of a data structure, and expect
>>the rest of the cacheline to be in cache as well. Though
>>in that case, maybe prefetch/prefetchw should be used
>>instead.
>
>
> Can you describe what the supposed improvement of the patch is?
>
From include/linux/prefetch.h:
"spin_lock_prefetch(x) - prefectches the spinlock *x for taking"
So this would reduce icache footprint and possibly memory
traffic on UP where taking a spinlock is a noop.
Granted, there aren't many users of spin_lock_prefetch at the
moment.
--
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com
next prev parent reply other threads:[~2005-08-04 13:16 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-08-04 13:07 [patch] make spin_lock_prefetch a noop for UP Nick Piggin
2005-08-04 13:10 ` Andi Kleen
2005-08-04 13:16 ` Nick Piggin [this message]
2005-08-04 13:25 ` Andi Kleen
2005-08-04 13:37 ` Nick Piggin
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