Message-ID: <4866C62A.2060808@zytor.com>
Date: Sat, 28 Jun 2008 16:15:54 -0700
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Anders H Kaseorg <andersk@MIT.EDU>
CC: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
       linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86_64: Patch paravirt inline replacements when loading
 modules
References: <alpine.DEB.1.10.0806280431510.31023@vinegar-pot.mit.edu> <4866BBC0.3000503@zytor.com> <alpine.DEB.1.10.0806281836020.31023@vinegar-pot.mit.edu>
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Anders H Kaseorg wrote:
> On Sat, 28 Jun 2008, H. Peter Anvin wrote:
>> Not having looked at this in detail, is this a *current* problem or a 
>> *future* problem, i.e. does it fix a bug that's currently in the kernel?
> 
> It's a current problem.  The current situation is that .parainstructions 
> are patched into the kernel core and modules on i386, but only the 
> kernel core on x86_64.  This results in a slight performance regression 
> in x86_64 modules, compared to the situation before .parainstructions 
> existed.  My patch restores full performance of x86_64 modules.

OK, it's a performance regression.  I don't think it makes sense for 
2.6.26, but it should definitely go into 2.6.27.

Thanks!

	-hpa

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