diff options
Diffstat (limited to 'tools/perf/Documentation')
| -rw-r--r-- | tools/perf/Documentation/perf-stat.txt | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt index 77081283856d..498bead1ef3b 100644 --- a/tools/perf/Documentation/perf-stat.txt +++ b/tools/perf/Documentation/perf-stat.txt @@ -236,6 +236,25 @@ filter out the startup phase of the program, which is often very different. Print statistics of transactional execution if supported. +--metric-no-group:: +By default, events to compute a metric are placed in weak groups. The +group tries to enforce scheduling all or none of the events. The +--metric-no-group option places events outside of groups and may +increase the chance of the event being scheduled - leading to more +accuracy. However, as events may not be scheduled together accuracy +for metrics like instructions per cycle can be lower - as both metrics +may no longer be being measured at the same time. + +--metric-no-merge:: +By default metric events in different weak groups can be shared if one +group contains all the events needed by another. In such cases one +group will be eliminated reducing event multiplexing and making it so +that certain groups of metrics sum to 100%. A downside to sharing a +group is that the group may require multiplexing and so accuracy for a +small group that need not have multiplexing is lowered. This option +forbids the event merging logic from sharing events between groups and +may be used to increase accuracy in this case. + STAT RECORD ----------- Stores stat data into perf data file. |