Messages in this thread |  | | | Date | Wed, 1 Apr 2009 11:39:42 +0200 | | From | Ingo Molnar <> | | Subject | Re: [PATCH 09/15] perf_counter tools: optionally scale counter values in perfstat mode |
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* Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:
> From: Paul Mackerras <paulus@samba.org> > > Impact: new functionality > > This adds add an option to the perfstat mode of kerneltop to scale > the reported counter values according to the fraction of time that > each counter gets to count. This is invoked with the -l option (I > used 'l' because s, c, a and e were all taken already.) This uses > the new PERF_RECORD_TOTAL_TIME_{ENABLED,RUNNING} read format > options. > > With this, we get output like this: > > $ ./perfstat -l -e 0:0,0:1,0:2,0:3,0:4,0:5 ./spin > > Performance counter stats for './spin': > > 4016072055 CPU cycles (events) (scaled from 66.53%) > 2005887318 instructions (events) (scaled from 66.53%) > 1762849 cache references (events) (scaled from 66.69%) > 165229 cache misses (events) (scaled from 66.85%) > 1001298009 branches (events) (scaled from 66.78%) > 41566 branch misses (events) (scaled from 66.61%) > > Wall-clock time elapsed: 2438.227446 msecs > > This also lets us detect when a counter is zero because the > counter never got to go on the CPU at all. In that case we print > <not counted> rather than 0.
Nice! Shouldnt this be the default mode of output?
I think we want to make users aware of the fact when output is sampled due to over-commit, rather than precise, agreed?
Ingo
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