#263 Using operf with multiple events, samples may be attributed to wrong event

None
open-fixed
None
5
2014-01-02
2013-12-19
Maynard Johnson
No

A serious bug was found that affects operf profiling with
multiple events. Samples for an event may be incorrectly
attributed to another event. For example, profiling on
a Sandybridge laptop with CPU_CLK_UNHALTED and INST_RETIRED
events produces the following summary counts from opreport:

CPU_CLK_UNHALTED |INST_RETIRED |
samples| %| samples| %|


  32412 100.000     20104 100.000 foo

Using operf to produce separate profiles for these two events
results in these sample counts:

CPU_CLK_UNHALTED |
samples| %|


  18962 100.000 foo

INST_RETIRED |
samples| %|


  33464 100.000 foo

The attached patch fixes this bug.

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Discussion

  • This patch was committed upstream on Dec 20, 2013.

     
    • status: open --> open-fixed
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