Re: Memory mapped IO vs Port IO

[Matthew Wilcox]

On Thu, Sep 11, 2003 at 06:31:36PM +0200, Andi Kleen wrote:
> On Thu, 11 Sep 2003 17:25:04 +0100
> Matthew Wilcox <willy@xxxxxxxxxx> wrote:
> > That's not true for MMIO writes which are posted.  They should take
> > no longer than a memory write.  For MMIO reads and PIO reads & writes,
> > you are, of course, correct.
> 
> Even a memory write is tens to hundres of cycles.

So are mispredicted branches.

-- 
"It's not Hollywood.  War is real, war is primarily not about defeat or
victory, it is about death.  I've seen thousands and thousands of dead bodies.
Do you think I want to have an academic debate on this subject?" -- Robert Fisk
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