Messages in this thread | | | Date | Mon, 06 Jul 2009 14:41:49 -0700 | From | (John A. Gregor) | Subject | Re: [PATCH] x86_64/__iowrite32_copy: don't use string move for PIO writes |
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"H. Peter Anvin" <hpa@zytor.com> wrote:
> John Gregor wrote: > > From: John Gregor <johng@diamond.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*?
More specifically, check out:
http://www.intel.com/Assets/PDF/specupdate/321324.pdf
Errata AAK6
-John Gregor
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