From ef91871c960ed1e9e790ed66840835fac87614b7 Mon Sep 17 00:00:00 2001 From: Ian Rogers Date: Sat, 27 May 2023 00:21:44 -0700 Subject: perf evlist: Propagate user CPU maps intersecting core PMU maps The CPU map for a non-core PMU gives a default CPU value for perf_event_open. For core PMUs the CPU map lists all CPUs the evsel may be opened on. If there are >1 core PMU, the CPU maps will list the CPUs for that core PMU, but the user_requested_cpus may contain CPUs that are invalid for the PMU and cause perf_event_open to fail. To avoid this, when propagating the CPU map for core PMUs intersect it with the CPU map of the PMU (the evsel's "own_cpus"). Add comments to __perf_evlist__propagate_maps to explain its somewhat complex behavior. Fix the related comments for system_wide in struct perf_evsel. Reviewed-by: Kan Liang Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ali Saidi Cc: Athira Rajeev Cc: Dmitrii Dolgov <9erthalion6@gmail.com> Cc: Huacai Chen Cc: Ingo Molnar Cc: James Clark Cc: Jing Zhang Cc: Jiri Olsa Cc: John Garry Cc: Kajol Jain Cc: Kang Minchul Cc: Leo Yan Cc: Madhavan Srinivasan Cc: Mark Rutland Cc: Mike Leach Cc: Ming Wang Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Rob Herring Cc: Sandipan Das Cc: Sean Christopherson Cc: Suzuki Poulouse Cc: Thomas Richter Cc: Will Deacon Cc: Xing Zhengjun Cc: coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org Link: https://lore.kernel.org/r/20230527072210.2900565-9-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/lib/perf/evlist.c | 25 ++++++++++++++++++++----- tools/lib/perf/include/internal/evsel.h | 6 +++--- 2 files changed, 23 insertions(+), 8 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/perf/evlist.c b/tools/lib/perf/evlist.c index 81e8b5fcd8ba..b8b066d0dc5e 100644 --- a/tools/lib/perf/evlist.c +++ b/tools/lib/perf/evlist.c @@ -36,18 +36,33 @@ void perf_evlist__init(struct perf_evlist *evlist) static void __perf_evlist__propagate_maps(struct perf_evlist *evlist, struct perf_evsel *evsel) { - /* - * We already have cpus for evsel (via PMU sysfs) so - * keep it, if there's no target cpu list defined. - */ if (evsel->system_wide) { + /* System wide: set the cpu map of the evsel to all online CPUs. */ perf_cpu_map__put(evsel->cpus); evsel->cpus = perf_cpu_map__new(NULL); + } else if (evlist->has_user_cpus && evsel->is_pmu_core) { + /* + * User requested CPUs on a core PMU, ensure the requested CPUs + * are valid by intersecting with those of the PMU. + */ + perf_cpu_map__put(evsel->cpus); + evsel->cpus = perf_cpu_map__intersect(evlist->user_requested_cpus, evsel->own_cpus); } else if (!evsel->own_cpus || evlist->has_user_cpus || - (!evsel->requires_cpu && perf_cpu_map__empty(evlist->user_requested_cpus))) { + (!evsel->requires_cpu && perf_cpu_map__has_any_cpu(evlist->user_requested_cpus))) { + /* + * The PMU didn't specify a default cpu map, this isn't a core + * event and the user requested CPUs or the evlist user + * requested CPUs have the "any CPU" (aka dummy) CPU value. In + * which case use the user requested CPUs rather than the PMU + * ones. + */ perf_cpu_map__put(evsel->cpus); evsel->cpus = perf_cpu_map__get(evlist->user_requested_cpus); } else if (evsel->cpus != evsel->own_cpus) { + /* + * No user requested cpu map but the PMU cpu map doesn't match + * the evsel's. Reset it back to the PMU cpu map. + */ perf_cpu_map__put(evsel->cpus); evsel->cpus = perf_cpu_map__get(evsel->own_cpus); } diff --git a/tools/lib/perf/include/internal/evsel.h b/tools/lib/perf/include/internal/evsel.h index 4d6f2a032f45..5cd220a61962 100644 --- a/tools/lib/perf/include/internal/evsel.h +++ b/tools/lib/perf/include/internal/evsel.h @@ -62,9 +62,9 @@ struct perf_evsel { int nr_members; /* * system_wide is for events that need to be on every CPU, irrespective - * of user requested CPUs or threads. Map propagation will set cpus to - * this event's own_cpus, whereby they will contribute to evlist - * all_cpus. + * of user requested CPUs or threads. Tha main example of this is the + * dummy event. Map propagation will set cpus for this event to all CPUs + * as software PMU events like dummy, have a CPU map that is empty. */ bool system_wide; /* -- cgit v1.2.3