Re: [Perfctr-devel] Re: Enabling RDPMC in user space by default

[David Gibson]

On Wed, Nov 30, 2005 at 12:39:20AM +0100, Andi Kleen wrote:
> > Well, if that's all you want them to use RDPMC 0 for, why not just make
> > PMCs programmable from userspace?
> 
> First we need to have a cycle counter PMC anyways for the NMI watchdog.
> So it can as well be used for other purposes.

But the watchdog doesn't require it to be in the same place on all
machines.  Exporting it turns an internal requirement into an ABI
point.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson
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