Re: Reading perf counters at ftrace trace boundaries

[Andi Kleen]

Karim Yaghmour <karim.yaghmour@xxxxxxxxxxx> writes:

> Wondering if there's a way for reading perf counters in the kernel. I'd
> like to read/record perf counters on ftrace function tracing
> entries/exits to provide a rundown of the value of various counters on
> function call boundaries.

KVM does it, see arch/x86/kvm/pmu.c. Essentially it would be doing RDPMC.

But the overhead will be likely very high, some sampling approach
is likely better.

-Andi

-- 
ak@xxxxxxxxxxxxxxx -- Speaking for myself only
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