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authorNamhyung Kim <namhyung@kernel.org>2021-11-05 23:58:47 +0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2021-11-06 23:54:42 +0300
commit3500eeebeda842e8499617b8983a4c55fd6bdfe3 (patch)
tree1dd42671be15ce3a962a9cd2624e33bebce94eb2 /tools/perf/util/python.c
parent88c42f4d6cb249eb68524282f8d4cc32f9059984 (diff)
downloadlinux-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.c12
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,