diff options
Diffstat (limited to 'tools/perf/Documentation/perf-stat.txt')
| -rw-r--r-- | tools/perf/Documentation/perf-stat.txt | 52 |
1 files changed, 28 insertions, 24 deletions
diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt index 8f789fa1242e..5af2e432b54f 100644 --- a/tools/perf/Documentation/perf-stat.txt +++ b/tools/perf/Documentation/perf-stat.txt @@ -422,7 +422,34 @@ See perf list output for the possible metrics and metricgroups. -A:: --no-aggr:: -Do not aggregate counts across all monitored CPUs. +--no-merge:: +Do not aggregate/merge counts across monitored CPUs or PMUs. + +When multiple events are created from a single event specification, +stat will, by default, aggregate the event counts and show the result +in a single row. This option disables that behavior and shows the +individual events and counts. + +Multiple events are created from a single event specification when: + +1. PID monitoring isn't requested and the system has more than one + CPU. For example, a system with 8 SMT threads will have one event + opened on each thread and aggregation is performed across them. + +2. Prefix or glob wildcard matching is used for the PMU name. For + example, multiple memory controller PMUs may exist typically with a + suffix of _0, _1, etc. By default the event counts will all be + combined if the PMU is specified without the suffix such as + uncore_imc rather than uncore_imc_0. + +3. Aliases, which are listed immediately after the Kernel PMU events + by perf list, are used. + +--hybrid-merge:: +Merge core event counts from all core PMUs. In hybrid or big.LITTLE +systems by default each core PMU will report its count +separately. This option forces core PMU counts to be combined to give +a behavior closer to having a single CPU type in the system. --topdown:: Print top-down metrics supported by the CPU. This allows to determine @@ -475,29 +502,6 @@ highlight 'tma_frontend_bound'. This metric may be drilled into with Error out if the input is higher than the supported max level. ---no-merge:: -Do not merge results from same PMUs. - -When multiple events are created from a single event specification, -stat will, by default, aggregate the event counts and show the result -in a single row. This option disables that behavior and shows -the individual events and counts. - -Multiple events are created from a single event specification when: -1. Prefix or glob matching is used for the PMU name. -2. Aliases, which are listed immediately after the Kernel PMU events - by perf list, are used. - ---hybrid-merge:: -Merge the hybrid event counts from all PMUs. - -For hybrid events, by default, the stat aggregates and reports the event -counts per PMU. But sometimes, it's also useful to aggregate event counts -from all PMUs. This option enables that behavior and reports the counts -without PMUs. - -For non-hybrid events, it should be no effect. - --smi-cost:: Measure SMI cost if msr/aperf/ and msr/smi/ events are supported. |