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From: Andi Kleen <andi@firstfloor.org>
To: "Ma, Ling" <ling.ma@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>, "mingo@elte.hu" <mingo@elte.hu>,
	"hpa@zytor.com" <hpa@zytor.com>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH RFC] [x86] Optimize copy-page by reducing impact from HW prefetch
Date: Thu, 23 Jun 2011 04:29:11 +0200	[thread overview]
Message-ID: <20110623022911.GM3263@one.firstfloor.org> (raw)
In-Reply-To: <C10D3FB0CD45994C8A51FEC1227CE22F239E8E4106@shsmsx502.ccr.corp.intel.com>

On Thu, Jun 23, 2011 at 09:01:19AM +0800, Ma, Ling wrote:
> Yes, I also have tested 64bit atom, it got 11.6% improvement.

That's a nice improvement, however I should add that in my experience 
copy_page micro benchmark improvements do not necessarily translate to
real world improvements. Most simple micro benchmark do not simulate
the typical page fault access pattern very well.

> Because older CPU almost all use prefetch-next-line mechanism, the patch should be useful to them.

Old in this case is P4 and ancient early stepping K8 only.

-Andi

  reply	other threads:[~2011-06-23  2:29 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-17 22:51 [PATCH RFC] [x86] Optimize copy-page by reducing impact from HW prefetch ling.ma
2011-06-22 20:05 ` Andi Kleen
2011-06-23  1:01   ` Ma, Ling
2011-06-23  2:29     ` Andi Kleen [this message]
2011-06-23  7:04   ` Ingo Molnar
2011-06-24  2:01     ` Ma, Ling
2011-06-24  2:09     ` Ma, Ling
2011-06-28 15:23     ` Ma, Ling
2011-07-01  8:10     ` Ma, Ling
2011-07-01 10:26     ` Ma, Ling

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