Re: [PATCH] x86_64/__iowrite32_copy: don't use string move for PIOwrites

[John A. Gregor]

"H. Peter Anvin" <hpa@xxxxxxxxx> wrote:

> John Gregor wrote:
> > From: John Gregor <johng@xxxxxxxxxxxxxxxxxxxxx>
> > 
> > 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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