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author | Namhyung Kim <namhyung@kernel.org> | 2021-11-05 23:58:47 +0300 |
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committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2021-11-06 23:54:42 +0300 |
commit | 3500eeebeda842e8499617b8983a4c55fd6bdfe3 (patch) | |
tree | 1dd42671be15ce3a962a9cd2624e33bebce94eb2 /tools/perf/util/python.c | |
parent | 88c42f4d6cb249eb68524282f8d4cc32f9059984 (diff) | |
download | linux-3500eeebeda842e8499617b8983a4c55fd6bdfe3.tar.xz |
perf evsel: Fix missing exclude_{host,guest} setting
The current logic for the perf missing feature has a bug that it can
wrongly clear some modifiers like G or H. Actually some PMUs don't
support any filtering or exclusion while others do. But we check it as
a global feature.
For example, the cycles event can have 'G' modifier to enable it only in
the guest mode on x86. When you don't run any VMs it'll return 0.
# perf stat -a -e cycles:G sleep 1
Performance counter stats for 'system wide':
0 cycles:G
1.000721670 seconds time elapsed
But when it's used with other pmu events that don't support G modifier,
it'll be reset and return non-zero values.
# perf stat -a -e cycles:G,msr/tsc/ sleep 1
Performance counter stats for 'system wide':
538,029,960 cycles:G
16,924,010,738 msr/tsc/
1.001815327 seconds time elapsed
This is because of the missing feature detection logic being global.
Add a hashmap to set pmu-specific exclude_host/guest features.
Committer notes:
Fix 'perf test python' by adding a stub for evsel__find_pmu() in
tools/perf/util/python.c, document that it is used so far only for the
above reasons so that if anybody needs this in the python binding
usecases, we can revisit this.
Reported-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Link: http://lore.kernel.org/lkml/20211105205847.120950-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util/python.c')
-rw-r--r-- | tools/perf/util/python.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c index 8feef3a05af7..563a9ba8954f 100644 --- a/tools/perf/util/python.c +++ b/tools/perf/util/python.c @@ -70,6 +70,18 @@ void perf_stat__collect_metric_expr(struct evlist *evsel_list) } /* + * This one is needed not to drag the PMU bandwagon, jevents generated + * pmu_sys_event_tables, etc and evsel__find_pmu() is used so far just for + * doing per PMU perf_event_attr.exclude_guest handling, not really needed, so + * far, for the perf python binding known usecases, revisit if this become + * necessary. + */ +struct perf_pmu *evsel__find_pmu(struct evsel *evsel __maybe_unused) +{ + return NULL; +} + +/* * Add this one here not to drag util/metricgroup.c */ int metricgroup__copy_metric_events(struct evlist *evlist, struct cgroup *cgrp, |