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-rw-r--r--tools/perf/Documentation/perf-stat.txt52
1 files changed, 28 insertions, 24 deletions
diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt
index 8f789fa124..5af2e432b5 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.