Messages in this thread |  | | Date | Mon, 31 May 2021 00:15:05 +0200 | From | Jiri Olsa <> | Subject | Re: [PATCH] perf tools: Move probing cgroup sampling support |
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On Thu, May 27, 2021 at 11:28:35AM -0700, Namhyung Kim wrote: > I found that checking cgroup sampling support using the missing > features doesn't work on old kernels. Because it added both > attr.cgroup bit and PERF_SAMPLE_CGROUP bit, it needs to check > whichever comes first (usually the actual event, not dummy). > > But it only checks the attr.cgroup bit which is set only in the dummy > event so cannot detect failtures due the sample bits. Also we don't > ignore the missing feature and retry, it'd be better checking it with > the API probing logic. > > Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@redhat.com>
thanks, jirka
> --- > tools/perf/builtin-record.c | 6 ++++++ > tools/perf/util/evsel.c | 6 +----- > tools/perf/util/evsel.h | 1 - > tools/perf/util/perf_api_probe.c | 10 ++++++++++ > tools/perf/util/perf_api_probe.h | 1 + > 5 files changed, 18 insertions(+), 6 deletions(-) > > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c > index bc3dd379eb67..71efe6573ee7 100644 > --- a/tools/perf/builtin-record.c > +++ b/tools/perf/builtin-record.c > @@ -2733,6 +2733,12 @@ int cmd_record(int argc, const char **argv) > rec->no_buildid = true; > } > > + if (rec->opts.record_cgroup && !perf_can_record_cgroup()) { > + pr_err("Kernel has no cgroup sampling support.\n"); > + err = -EINVAL; > + goto out_opts; > + } > + > if (rec->opts.kcore) > rec->data.is_dir = true; > > diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c > index 4a3cd1b5bb33..2462584d0ee5 100644 > --- a/tools/perf/util/evsel.c > +++ b/tools/perf/util/evsel.c > @@ -1217,7 +1217,7 @@ void evsel__config(struct evsel *evsel, struct record_opts *opts, > attr->namespaces = track; > > if (opts->record_cgroup) { > - attr->cgroup = track && !perf_missing_features.cgroup; > + attr->cgroup = track; > evsel__set_sample_bit(evsel, CGROUP); > } > > @@ -1933,10 +1933,6 @@ static int evsel__open_cpu(struct evsel *evsel, struct perf_cpu_map *cpus, > perf_missing_features.data_page_size = true; > pr_debug2_peo("Kernel has no PERF_SAMPLE_DATA_PAGE_SIZE support, bailing out\n"); > goto out_close; > - } else if (!perf_missing_features.cgroup && evsel->core.attr.cgroup) { > - perf_missing_features.cgroup = true; > - pr_debug2_peo("Kernel has no cgroup sampling support, bailing out\n"); > - goto out_close; > } else if (!perf_missing_features.branch_hw_idx && > (evsel->core.attr.branch_sample_type & PERF_SAMPLE_BRANCH_HW_INDEX)) { > perf_missing_features.branch_hw_idx = true; > diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h > index 75cf5dbfe208..fecf13c0e4da 100644 > --- a/tools/perf/util/evsel.h > +++ b/tools/perf/util/evsel.h > @@ -168,7 +168,6 @@ struct perf_missing_features { > bool bpf; > bool aux_output; > bool branch_hw_idx; > - bool cgroup; > bool data_page_size; > bool code_page_size; > bool weight_struct; > diff --git a/tools/perf/util/perf_api_probe.c b/tools/perf/util/perf_api_probe.c > index 829af17a0867..020411682a3c 100644 > --- a/tools/perf/util/perf_api_probe.c > +++ b/tools/perf/util/perf_api_probe.c > @@ -103,6 +103,11 @@ static void perf_probe_build_id(struct evsel *evsel) > evsel->core.attr.build_id = 1; > } > > +static void perf_probe_cgroup(struct evsel *evsel) > +{ > + evsel->core.attr.cgroup = 1; > +} > + > bool perf_can_sample_identifier(void) > { > return perf_probe_api(perf_probe_sample_identifier); > @@ -182,3 +187,8 @@ bool perf_can_record_build_id(void) > { > return perf_probe_api(perf_probe_build_id); > } > + > +bool perf_can_record_cgroup(void) > +{ > + return perf_probe_api(perf_probe_cgroup); > +} > diff --git a/tools/perf/util/perf_api_probe.h b/tools/perf/util/perf_api_probe.h > index f12ca55f509a..b104168efb15 100644 > --- a/tools/perf/util/perf_api_probe.h > +++ b/tools/perf/util/perf_api_probe.h > @@ -12,5 +12,6 @@ bool perf_can_record_switch_events(void); > bool perf_can_record_text_poke_events(void); > bool perf_can_sample_identifier(void); > bool perf_can_record_build_id(void); > +bool perf_can_record_cgroup(void); > > #endif // __PERF_API_PROBE_H > -- > 2.32.0.rc0.204.g9fa02ecfa5-goog >
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