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

Mathieu Desnoyers
2009-06-15T19:04:50Z

* Peter Zijlstra (a.p.zijlstra@chello.nl) wrote:
> On Mon, 2009-06-15 at 14:48 -0400, Mathieu Desnoyers wrote:
> > we should not care that much about the performance hit of
> > saving/restoring the cr2 register at each nmi entry/exit.
>
> But we do, perf counters very much cares about nmi performance.
>

To a point where it cannot afford a simple register save/restore ?

There is "caring" and "_caring_". I am tempted to ask what NMI handler
execution frequency you have in mind here to figure out if we are not
trying to optimize sub-nanoseconds per minutes. ;)

Mathieu

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Mathieu Desnoyers
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