Re: CPA patchset

[Andi Kleen]

On Thu, Jan 10, 2008 at 11:04:43AM +0100, Ingo Molnar wrote:
> 
> * Andi Kleen <ak@xxxxxxx> wrote:
> 
> > >   WBINVD isnt particular fast (takes a few msecs), but why is that a 
> > >   problem? Drivers dont do high-frequency ioremap-ing. It's 
> > >   typically only done at driver/device startup and that's it.
> > 
> > Actually graphics drivers can do higher frequency allocation of WC 
> > memory (with PAT) support.
> 
> but that's not too smart: why dont they use WB plus cflush instead? 

Because they need to access it WC for performance.

> ioremap() will always be slow and we dont care about stupid uses of it.

Uninterruptible msec latencies are too slow even for slow path
initialization code imho.

-Andi
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