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From: James Morris <jmorris@intercode.com.au>
To: Linus Torvalds <torvalds@transmeta.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Performance issue in 2.5.32+
Date: Tue, 10 Sep 2002 02:06:04 +1000 (EST)	[thread overview]
Message-ID: <Mutt.LNX.4.44.0209100150490.25061-100000@blackbird.intercode.com.au> (raw)
In-Reply-To: <Pine.LNX.4.44.0209081055310.14734-100000@home.transmeta.com>

On Sun, 8 Sep 2002, Linus Torvalds wrote:

> I don't really see anythign very suspicious in the 31->32 changelogs. 
> Somebody else already mentioned TLS etc, but that shouldn't really be 
> noticeable...

I've now tracked the problem to the introduction of the new mtrr code, and
backing it out for 2.5.32 restores original performance.  From what I can 
tell, the new code is not handling a bios/hardware bug that the old code 
was.

The old mtrr code says this during bootup:
 mtrr: your CPUs had inconsistent fixed MTRR settings
 mtrr: your CPUs had inconsistent variable MTRR settings
 mtrr: probably your BIOS does not setup all CPUs

While the new code just says:
 mtrr: SMP support incomplete for this vendor

The peformance hit is basically the same as when the old mtrr code is 
disabled.  I'll have a poke around and see if I can find out why the new 
mtrr code isn't handling the problem.


- James
-- 
James Morris
<jmorris@intercode.com.au>



  reply	other threads:[~2002-09-09 16:01 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-09-08 11:46 James Morris
2002-09-08 11:57 ` Andi Kleen
2002-09-08 12:55   ` James Morris
2002-09-08 15:45 ` Linus Torvalds
2002-09-08 17:40   ` James Morris
2002-09-08 18:09     ` Linus Torvalds
2002-09-09 16:06       ` James Morris [this message]
2002-09-08 13:19 rwhron

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