Re: [tip:perfcounters/core] perf_counter: x86: Fix call-chain support to use NMI-safe methods

[Ingo Molnar <mingo@xxxxxxx>]

* Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx> wrote:

> > If it's a slowdown then the decision is easy: we dont want this, 
> > we want to push the overhead into the sampling code, away from 
> > common codepaths.
> 
> I did not try to make the "hand unroll + ret" the default. I 
> therefore don't know if it is faster or slower than iret. But I 
> prefered to stay on the safe side and only modify the exceptions 
> nested within NMI handlers.

hm, i misread that bit then. Too bad.

Btw., that speedup question is still valid. (Just not relevant here 
and now.)

	Ingo
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