linux-kernel - Re: [PATCH] x86_64/__iowrite32_copy: don't use string move for PIO writes

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Message-ID: <4A526CE6.30200@zytor.com>
Date:	Mon, 06 Jul 2009 14:30:14 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	John Gregor <john.gregor@...gic.com>
CC:	linux-kernel@...r.kernel.org,
	John Gregor <johng@...mond.mv.qlogic.com>,
	Ralph Campbell <ralph.campbell@...gic.com>
Subject: Re: [PATCH] x86_64/__iowrite32_copy: don't use string move for PIO
 writes

John Gregor wrote:
> From: John Gregor <johng@...mond.mv.qlogic.com>
> 
> Some processors can write the same word more than once if the movs
> instruction is used. This version uses normal memory move instructions
> and gets the same performance since the speed is limited by PCIe and
> write combining.
> 

Which processors do that *when addressing I/O memory*?

	-hpa
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