Messages in this thread | | | Subject | Re: [RFC][PATCH 0/6] perf: x86 RDPMC and RDTSC support | From | Peter Zijlstra <> | Date | Wed, 21 Dec 2011 22:41:07 +0100 |
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On Wed, 2011-12-21 at 16:32 -0500, Vince Weaver wrote:
> * One, is it possible to detect at runtime that rdpmc() is supported? > Maybe a field in the mmap'd buffer that can be read?
Ingo suggested a similar thing, will implement (although Christmas might interfere with delivery timelines etc..).
> * Second, if I try a start / run 100M instructions / read > and measure retired instructions I get: > 281474977711543 instructions > This is 0x10000000f45b7 which is 1<<48 + 100M. I guess an artifact > of how the counters are set up? Is it possible to have this start > at 0?
Its supposed to be 0 based, clearly I messed up something and need to go figure out what. Thanks for reporting.
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