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

Avi Kivity
2009-06-15T19:16:55Z

On 06/15/2009 10:02 PM, Peter Zijlstra wrote:
> Ah, well, I have no idea who expensive cr2 is, if its like a regular
> register then it should be fine. If however its tons more expensive then
> we should really avoid it.
>
>

IIRC it's pretty cheap, I measured it once when tuning the kvm context
switch code. I don't recall the exact numbers.

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