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From: Pavel Machek <pavel@ucw.cz>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: John Alvord <jalvo@mbay.net>,
	Thunder from the hill <thunder@ngforever.de>,
	Pablo Fischer <exilion@yifan.net>,
	Mark Hahn <hahn@physics.mcmaster.ca>,
	linux-kernel@vger.kernel.org
Subject: Re: StackPages errors (CALLTRACE)
Date: Tue, 9 Jul 2002 05:03:00 +0200	[thread overview]
Message-ID: <20020709030259.GA113@elf.ucw.cz> (raw)
In-Reply-To: <E17QaN6-0004Ci-00@the-village.bc.nu>

Hi!

> > There has also been a patch on L-K which implments CMOV on prior-PPro
> > processors. john
> 
> It has a hideous overhead. Just dont use cmov blindly in kernels. The kernel 
> stuff will take care not to let the compiler stick cmov instructions into
> a non ppro+ kernel

Not only nasty overhead but potential nasty implications. You get
exception where you'd normaly get simple instruction. Do NOT use cmov
emulation for kernel.
									Pavel
-- 
Worst form of spam? Adding advertisment signatures ala sourceforge.net.
What goes next? Inserting advertisment *into* email?

  reply	other threads:[~2002-07-09 13:11 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <Pine.LNX.4.33.0207051154160.14284-100000@coffee.psychology.mcmaster.ca>
2002-07-05 17:06 ` Pablo Fischer
2002-07-05 17:43   ` Thunder from the hill
2002-07-05 19:50     ` John Alvord
2002-07-05 21:12       ` Alan Cox
2002-07-09  3:03         ` Pavel Machek [this message]
2002-07-05  6:06 Pablo Fischer
2002-07-05  9:24 ` Gabriel Paubert
2002-07-05 16:47   ` Pablo Fischer
2002-07-05 20:00     ` Diego Calleja
2002-07-05 21:21     ` Alan Cox

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