Re: [patch] Performance Counters for Linux, v2

[Ingo Molnar]

* David Miller <davem@xxxxxxxxxxxxx> wrote:

> From: Ingo Molnar <mingo@xxxxxxx>
> Date: Tue, 9 Dec 2008 12:02:46 +0100
> 
> > 
> > * stephane eranian <eranian@xxxxxxxxxxxxxx> wrote:
> > 
> > > > There's also more generic x86 support: all 4 generic PMCs of Nehalem 
> > > > / Core i7 are supported - i've run 4 instances of KernelTop and they 
> > > > used up four separate PMCs.
> > >
> > > Core/Atom have 5 counters, Nehalem has 7. Why are you not using all of 
> > > them already?
> > 
> > no, Nehalem has 4 generic purpose PMCs and 3 fixed-purpose PMCs (7 
> > total),
>  ...
> > Saying that it has 7 is misleading.
> 
> Even you just did.

which portion of my point stressing the general purpose attribute was 
unclear to you?

Saying it has 7 is misleading in the same way as if i told you now: 
"look, i have four eyes!". (they are: left eye looking right, left eye 
looking left, right eye looking left and right eye looking right)

Nehalem has 4 general purpose PMCs, not 7. Yes, it has 7 counters but 
they are not all general purpose. The P4 has 18.

	Ingo
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