Re: [RFC][PATCH 0/6] perf: x86 RDPMC and RDTSC support

From: Vince Weaver
Date: Mon Nov 21 2011 - 10:01:53 EST


On Mon, 21 Nov 2011, Peter Zijlstra wrote:

> These few patches implement x86 RDPMC support and add an extention to the self
> monitoring data to also allow additional time updates using userspace TSC reads.
>
> There's a few loose ends, but it mostly seems to work.

I'll have to test these out.

I have some low-level benchmarks I've been working on, you can see some
preliminary results here:
http://web.eecs.utk.edu/~vweaver1/projects/perf-events/benchmarks/

perf_events was lagging behind perfmon2 and perfctr in self-monitoring
overhead, but maybe these changes will help that.

perf_event overhead got a lot worse between 2.6.32 and 3.0, I'm mid-bisect
on that trying to isolate the cause.

Vince

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