From 3500eeebeda842e8499617b8983a4c55fd6bdfe3 Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Fri, 5 Nov 2021 13:58:47 -0700 Subject: 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 Signed-off-by: Namhyung Kim Cc: Andi Kleen Cc: Ian Rogers Cc: Jiri Olsa Cc: Peter Zijlstra Cc: Ravi Bangoria Link: http://lore.kernel.org/lkml/20211105205847.120950-1-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/python.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'tools/perf/util/python.c') 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 @@ -69,6 +69,18 @@ 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 */ -- cgit