Messages in this thread | | | Date | Fri, 7 Aug 2009 13:26:34 +0200 | From | Ingo Molnar <> | Subject | Re: [patch] x86, perf_counter, bts: add bts to perf_counter |
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btw., the number of samples seems to be varying too widely:
titan:~> for ((i=0;i<10;i++)); do perf record -f -e branches:u -c 1 true 2>/dev/null; perf report | head -1; done # Samples: 28784 # Samples: 24063 # Samples: 22788 # Samples: 30449 # Samples: 15335 # Samples: 30557 # Samples: 24010 # Samples: 23866 # Samples: 24877 # Samples: 24330
compared to the branch-stat itself:
titan:~> perf stat -v --repeat 10 -e branches:u true [ perf stat: executing run #1 ... ] [ perf stat: executing run #2 ... ] [ perf stat: executing run #3 ... ] [ perf stat: executing run #4 ... ] [ perf stat: executing run #5 ... ] [ perf stat: executing run #6 ... ] [ perf stat: executing run #7 ... ] [ perf stat: executing run #8 ... ] [ perf stat: executing run #9 ... ] [ perf stat: executing run #10 ... ]
Performance counter stats for 'true' (10 runs):
23851 branches ( +- 0.000% )
0.000639653 seconds time elapsed ( +- 2.474% )
do we lose records in the recording?
Ingo
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