Messages in this thread | | | Date | Mon, 15 Jun 2009 14:59:07 -0400 | From | Mathieu Desnoyers <> | Subject | Re: [tip:perfcounters/core] perf_counter: x86: Fix call-chain support to use NMI-safe methods |
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* 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
-- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
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