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From: "H. Peter Anvin" <hpa@zytor.com>
To: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Ingo Molnar <mingo@elte.hu>,
	akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
	"Frank Ch. Eigler" <fche@redhat.com>
Subject: Re: [patch 0/2] Immediate Values - jump patching update
Date: Sun, 04 May 2008 14:05:26 -0700	[thread overview]
Message-ID: <481E2516.7070600@zytor.com> (raw)
In-Reply-To: <20080504145430.GA23137@Krystal>

Mathieu Desnoyers wrote:
> 
> Following your own suggestion, why don't we fix gcc and make it
> interleave unlikely blocks less heavily with hot blocks ?
> 

Doing this with compiler support is definitely The Right Thing, so I 
think this is the best way.

>> Furthermore, modern CPUs often speculatively fetch *both* 
>> branches of a conditional.
>>
>> This is actually the biggest motivation for patching static branches.
> 
> Agreed. I'd like to find some info about which microarchitectures you
> have in mind. Intel Core 2 ?

Not sure about Core 2, although Core 2 definitely can track down the 
wrong branch on a mispredict.

> Let's fix gcc ! ;)

Sounds great :)

	-hpa


      reply	other threads:[~2008-05-04 21:09 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-04-28  3:34 [patch 0/2] Immediate Values - jump patching update Mathieu Desnoyers
2008-04-28  3:34 ` [patch 1/2] Immediate Values - jump liveliness Mathieu Desnoyers
2008-04-28  3:34 ` [patch 2/2] Markers - use imv_cond " Mathieu Desnoyers
2008-04-28 12:48 ` [patch 0/2] Immediate Values - jump patching update Ingo Molnar
2008-04-28 14:35   ` Mathieu Desnoyers
2008-04-28 17:21 ` H. Peter Anvin
2008-04-28 20:25   ` Ingo Molnar
2008-04-28 21:03     ` H. Peter Anvin
2008-04-28 22:11       ` Ingo Molnar
2008-04-28 22:25         ` H. Peter Anvin
2008-04-28 22:44           ` Ingo Molnar
2008-04-28 23:06             ` H. Peter Anvin
2008-04-29  0:47               ` Frank Ch. Eigler
2008-04-29  1:08                 ` H. Peter Anvin
2008-04-29 12:08                   ` Ingo Molnar
2008-05-14 14:53                     ` Pavel Machek
2008-04-29  1:46               ` Mathieu Desnoyers
2008-04-29  2:07                 ` H. Peter Anvin
2008-04-29 12:18                   ` Mathieu Desnoyers
2008-04-29 15:35                     ` H. Peter Anvin
2008-05-04 14:54                       ` Mathieu Desnoyers
2008-05-04 21:05                         ` H. Peter Anvin [this message]

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