Messages in this thread Patch in this message | | | Date | Wed, 22 Apr 2020 10:46:35 +0200 | From | Jiri Olsa <> | Subject | Re: [PATCH v2] perf record: add dummy event during system wide synthesis |
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On Mon, Apr 20, 2020 at 11:11:03PM -0700, Ian Rogers wrote: > During the processing of /proc during event synthesis new processes may > start. Add a dummy event if /proc is to be processed, to capture mmaps > for starting processes. This reuses the existing logic for > initial-delay. > > v2 fixes the dummy event configuration and a branch stack issue.
heya, it's breaking attr tests for me:
[jolsa@krava perf]$ sudo ./perf test -v 17 17: Setup struct perf_event_attr : --- start --- test child forked, pid 1046560 running './tests/attr/test-record-graph-default' running './tests/attr/test-record-raw' running './tests/attr/test-record-branch-filter-any' running './tests/attr/test-record-freq' running './tests/attr/test-record-branch-any' running './tests/attr/test-stat-group1' running './tests/attr/test-record-no-samples' running './tests/attr/test-record-graph-dwarf' running './tests/attr/test-stat-C0' running './tests/attr/test-stat-basic' running './tests/attr/test-record-group' running './tests/attr/test-record-branch-filter-k' running './tests/attr/test-stat-group' running './tests/attr/test-record-C0' expected config=0, got 9 expected sample_type=391, got 455 expected disabled=1, got 0 FAILED './tests/attr/test-record-C0' - match failure test child finished with -1 ---- end ---- Setup struct perf_event_attr: FAILED!
jirka
> > Suggested-by: Stephane Eranian <eranian@google.com> > Signed-off-by: Ian Rogers <irogers@google.com> > --- > tools/perf/builtin-record.c | 19 ++++++++++++++----- > tools/perf/util/evsel.c | 5 ++++- > 2 files changed, 18 insertions(+), 6 deletions(-) > > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c > index 1ab349abe904..8d1e93351298 100644 > --- a/tools/perf/builtin-record.c > +++ b/tools/perf/builtin-record.c > @@ -805,19 +805,28 @@ static int record__open(struct record *rec) > int rc = 0; > > /* > - * For initial_delay we need to add a dummy event so that we can track > - * PERF_RECORD_MMAP while we wait for the initial delay to enable the > - * real events, the ones asked by the user. > + * For initial_delay or system wide, we need to add a dummy event so > + * that we can track PERF_RECORD_MMAP to cover the delay of waiting or > + * event synthesis. > */ > - if (opts->initial_delay) { > + if (opts->initial_delay || target__has_cpu(&opts->target)) { > if (perf_evlist__add_dummy(evlist)) > return -ENOMEM; > > + /* Disable tracking of mmaps on lead event. */ > pos = evlist__first(evlist); > pos->tracking = 0; > + /* Set up dummy event. */ > pos = evlist__last(evlist); > pos->tracking = 1; > - pos->core.attr.enable_on_exec = 1; > + /* > + * Enable the dummy event when the process is forked for > + * initial_delay, immediately for system wide. > + */ > + if (opts->initial_delay) > + pos->core.attr.enable_on_exec = 1; > + else > + pos->immediate = 1; > } > > perf_evlist__config(evlist, opts, &callchain_param); > diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c > index 6a571d322bb2..ca8f9533d8f9 100644 > --- a/tools/perf/util/evsel.c > +++ b/tools/perf/util/evsel.c > @@ -1163,11 +1163,14 @@ void perf_evsel__config(struct evsel *evsel, struct record_opts *opts, > } > > /* > + * A dummy event never triggers any actual counter and therefore > + * cannot be used with branch_stack. > + * > * For initial_delay, a dummy event is added implicitly. > * The software event will trigger -EOPNOTSUPP error out, > * if BRANCH_STACK bit is set. > */ > - if (opts->initial_delay && is_dummy_event(evsel)) > + if (is_dummy_event(evsel)) > perf_evsel__reset_sample_bit(evsel, BRANCH_STACK); > } > > -- > 2.26.1.301.g55bc3eb7cb9-goog >
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