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From: Andi Kleen <andi@firstfloor.org>
To: Mark Mitchell <mark@codesourcery.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>,
	 gcc-patches@gcc.gnu.org,  "H.J. Lu" <hjl.tools@gmail.com>,
	 "Fang\, Changpeng" <Changpeng.Fang@amd.com>,
	 "rguenther\@suse.de" <rguenther@suse.de>,
	 "sebpop\@gmail.com" <sebpop@gmail.com>,
	 Zdenek Dvorak <rakdver@kam.mff.cuni.cz>,
	 Maxim Kuvyrkov <maxim@codesourcery.com>
Subject: Re: [PATCH] Enabling Software Prefetching by Default at -O3
Date: Sun, 20 Jun 2010 04:29:00 -0000	[thread overview]
Message-ID: <87mxuqiy0b.fsf@basil.nowhere.org> (raw)
In-Reply-To: <4C1D2304.5080007@codesourcery.com> (Mark Mitchell's message of	"Sat, 19 Jun 2010 13:05:24 -0700")

Mark Mitchell <mark@codesourcery.com> writes:
>
> Yes, that might be a good idea for i7.
>
> But, in the meantime, I think we should get a version of the patch that
> turns on prefetching on AMD CPUs with -O3.  There's no reason to demand
> consistency for all CPUs and it clearly benefits the AMD CPUs.
> Changpeng, would you please submit a patch that activates this
> optimization only with tuning for AMD CPUs?

On i7 it will be likely still a win if hardware prefetch is disabled
in the BIOS. Most BIOS have a setting like this.

Unfortunately this cannot be easily detected by a program.

-Andi
-- 
ak@linux.intel.com -- Speaking for myself only.

  reply	other threads:[~2010-06-19 20:11 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-06-15 22:21 Fang, Changpeng
2010-06-15 22:24 ` H.J. Lu
2010-06-15 22:28   ` Fang, Changpeng
2010-06-15 22:44     ` H.J. Lu
2010-06-15 22:47       ` Fang, Changpeng
2010-06-15 23:42         ` Mark Mitchell
2010-06-16  0:30           ` H.J. Lu
2010-06-16  3:43             ` Mark Mitchell
2010-06-18  8:51               ` Christian Borntraeger
2010-06-18 18:00                 ` Fang, Changpeng
2010-06-19  0:30             ` H.J. Lu
2010-06-20  0:11               ` Christian Borntraeger
2010-06-20  2:34                 ` Mark Mitchell
2010-06-20  4:29                   ` Andi Kleen [this message]
2010-06-22 23:40                   ` Fang, Changpeng
2010-06-23  6:21                     ` Christian Borntraeger
2010-06-23  9:26                       ` Richard Guenther
2010-06-23 12:02                         ` Joseph S. Myers
2010-06-23 12:30                         ` Christian Borntraeger
2010-06-23 13:13                           ` Manuel López-Ibáñez
2010-06-24 23:37                   ` Fang, Changpeng
2010-06-25 11:48                     ` Richard Guenther
2010-06-25 20:16                       ` Sebastian Pop
2010-06-26 17:01                         ` Richard Guenther
2010-06-26 17:30                           ` Richard Guenther
2010-06-26 17:38                           ` Jan Hubicka
2010-06-26 18:23                             ` Jan Hubicka
2010-06-25 12:29                     ` Christian Borntraeger
2010-07-02 12:46                       ` [PATCH] Enabling Software Prefetching by Default@-O3 Ulrich Weigand
2010-06-18  9:13 ` [PATCH] Enabling Software Prefetching by Default at -O3 Andreas Krebbel
2010-06-18  9:26 ` Andreas Krebbel

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