From: Andi Kleen <[email protected]> Automatically disable collecting branch flags and cycles with --call-graph lbr. This allows avoiding a bunch of extra MSR reads in the PMI on Skylake.
When the kernel doesn't support the new flags they are automatically cleared in the fallback code. Signed-off-by: Andi Kleen <[email protected]> --- tools/perf/util/evsel.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index c886b9f..4d8a86c 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -557,6 +557,8 @@ perf_evsel__config_callgraph(struct perf_evsel *evsel, "Falling back to framepointers.\n"); } else { perf_evsel__set_sample_bit(evsel, BRANCH_STACK); + perf_evsel__set_sample_bit(evsel, BRANCH_NO_CYCLES); + perf_evsel__set_sample_bit(evsel, BRANCH_NO_FLAGS); attr->branch_sample_type = PERF_SAMPLE_BRANCH_USER | PERF_SAMPLE_BRANCH_CALL_STACK; } @@ -1167,6 +1169,8 @@ fallback_missing_features: evsel->attr.mmap2 = 0; if (perf_missing_features.exclude_guest) evsel->attr.exclude_guest = evsel->attr.exclude_host = 0; + evsel->attr.sample_type &= ~(PERF_SAMPLE_BRANCH_NO_FLAGS| + PERF_SAMPLE_BRANCH_NO_CYCLES); retry_sample_id: if (perf_missing_features.sample_id_all) evsel->attr.sample_id_all = 0; -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
