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authorIan Rogers <irogers@google.com>2023-12-14 09:02:56 +0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2023-12-15 00:24:38 +0300
commit6f33e6fa29d0366d6e5b3ea2930dbc0b648151fe (patch)
tree2b08f3618a8ff779f2094f7ef9a2ae424ebe52a4 /tools/perf/Documentation
parent1bc479d665bc25a9a4e8168d5b400a47491511f9 (diff)
downloadlinux-6f33e6fa29d0366d6e5b3ea2930dbc0b648151fe.tar.xz
perf stat: Combine the -A/--no-aggr and --no-merge options
The -A or --no-aggr option disables aggregation of core events: $ perf stat -A -e cycles,data_total -a true Performance counter stats for 'system wide': CPU0 1,287,665 cycles CPU1 1,831,681 cycles CPU2 27,345,998 cycles CPU3 1,964,799 cycles CPU4 236,174 cycles CPU5 3,302,825 cycles CPU6 9,201,446 cycles CPU7 1,403,043 cycles CPU0 110.90 MiB data_total 0.008961761 seconds time elapsed The --no-merge option disables the aggregation of uncore events: $ perf stat --no-merge -e cycles,data_total -a true Performance counter stats for 'system wide': 38,482,778 cycles 15.04 MiB data_total [uncore_imc_free_running_1] 15.00 MiB data_total [uncore_imc_free_running_0] 0.005915155 seconds time elapsed Having two options confuses users who generally don't appreciate the difference in PMUs. Keep all the options but make it so they all disable aggregation both of core and uncore events: $ perf stat -A -e cycles,data_total -a true Performance counter stats for 'system wide': CPU0 85,878 cycles CPU1 88,179 cycles CPU2 60,872 cycles CPU3 3,265,567 cycles CPU4 82,357 cycles CPU5 83,383 cycles CPU6 84,156 cycles CPU7 220,803 cycles CPU0 2.38 MiB data_total [uncore_imc_free_running_0] CPU0 2.38 MiB data_total [uncore_imc_free_running_1] 0.001397205 seconds time elapsed Update the relevant 'perf stat' man page information. Reviewed-by: Kan Liang <kan.liang@linux.intel.com> Signed-off-by: Ian Rogers <irogers@google.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Athira Jajeev <atrajeev@linux.vnet.ibm.com> Cc: Changbin Du <changbin.du@huawei.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Clark <james.clark@arm.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: John Garry <john.g.garry@oracle.com> Cc: K Prateek Nayak <kprateek.nayak@amd.com> Cc: Kaige Ye <ye@kaige.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/20231214060256.2094017-1-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/Documentation')
-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 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.