Messages in this thread | | | Date | Fri, 3 Jul 2009 18:18:04 +1000 | From | Paul Mackerras <> | Subject | Re: [PATCH 2/6 -tip] perf stat: treat same behaviour for all CYCLES and CLOCKS |
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Ingo Molnar writes:
> Other 'compound' events might be possible too: for example a new > cache-hits field could be is cache-refs minus cache-misses.
Hmmm, on the MPC7450 family there are events for cache-hits and cache-misses, so there it would be nice to be able to ask for cache-refs and have it compute cache-hits plus cache-misses.
> I.e. the simplest model for 'compound' events would be: > > X = A / B > X = A - B > X = A + B > > We could list them in the event table, with a flag that specifies > which arithmetic operation connects two 'atomic' counters. > > Then the adding of a new compound event would only be the matter of > adding one more line to the event table.
Sounds nice. If we do this we should ensure that the two events get put into one group if possible.
Paul.
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