From 9f21b815be863218192f42f9f5bf78b75f8738e0 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Thu, 8 Sep 2016 11:21:51 +0100 Subject: [PATCH] perf evlist: Only open events on CPUs an evsel permits In systems with heterogeneous CPU PMUs, it's possible for each evsel to cover a distinct set of CPUs, and hence the cpu_map associated with each evsel may have a distinct idx<->id mapping. Any of these may be distinct from the evlist's cpu map. Events can be tied to the same fd so long as they use the same per-cpu ringbuffer (i.e. so long as they are on the same CPU). To acquire the correct FDs, we must compare the Linux logical IDs rather than the evsel or evlist indices. This path adds logic to perf_evlist__mmap_per_evsel to handle this, translating IDs as required. As PMUs may cover a subset of CPUs from the evlist, we skip the CPUs a PMU cannot handle. Without this patch, perf record may try to mmap erroneous FDs on heterogeneous systems, and will bail out early rather than running the workload. Signed-off-by: Mark Rutland Acked-by: Jiri Olsa Cc: Alexander Shishkin Cc: Mark Rutland Cc: Peter Zijlstra Cc: Will Deacon Link: http://lkml.kernel.org/r/1473330112-28528-7-git-send-email-mark.rutland@arm.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/evlist.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index 097b3ed77fdd..ea34c5a32c11 100644 --- a/tools/perf/util/evlist.c +++ b/tools/perf/util/evlist.c @@ -1032,16 +1032,18 @@ perf_evlist__should_poll(struct perf_evlist *evlist __maybe_unused, } static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx, - struct mmap_params *mp, int cpu, + struct mmap_params *mp, int cpu_idx, int thread, int *_output, int *_output_backward) { struct perf_evsel *evsel; int revent; + int evlist_cpu = cpu_map__cpu(evlist->cpus, cpu_idx); evlist__for_each_entry(evlist, evsel) { struct perf_mmap *maps = evlist->mmap; int *output = _output; int fd; + int cpu; if (evsel->attr.write_backward) { output = _output_backward; @@ -1060,6 +1062,10 @@ static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx, if (evsel->system_wide && thread) continue; + cpu = cpu_map__idx(evsel->cpus, evlist_cpu); + if (cpu == -1) + continue; + fd = FD(evsel, cpu, thread); if (*output == -1) { -- 2.20.1