Messages in this thread | | | Date | Tue, 21 Nov 2017 13:40:22 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH v6 2/6] perf record: Get the first sample time and last sample time |
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Em Mon, Nov 06, 2017 at 08:21:07PM +0800, Jin Yao escreveu: > In perf record, it's walked on all samples yet. So it's very easy to get
"In the default 'perf record' configuration, all samples are processed, to create the HEADER_BUILD_ID table. So..."
> the first/last samples and save the time to perf file header via the > function write_sample_time(). > > In later, perf report/script will fetch the time from perf file header.
Later, at post processing time, ...
> > Change log: > ----------- > v6: Currently '--buildid-all' is not enabled at default. So the walking
--no-buildid-all, right?
> on all samples is the default operation. There is no big overhead > to calculate the timestamp boundary in process_sample_event handler > once we already go through all samples. So the timestamp boundary > calculation is enabled by default when '--buildid-all' is not enabled. > > While if '--buildid-all' is enabled, we creates a new option > "--timestamp-boundary" for user to decide if it enables the > timestamp boundary calculation. > > v5: There is an issue that the sample walking can only work when > '--buildid-all' is not enabled. So we need to let the walking > be able to work even if '--buildid-all' is enabled and let the > processing skips the dso hit marking for this case. > > At first, I want to provide a new option "--record-time-boundaries". > While after consideration, I think a new option is not very > necessary. > > v3: Remove the definitions of first_sample_time and last_sample_time > from struct record and directly save them in perf_evlist. > > Signed-off-by: Jin Yao <yao.jin@linux.intel.com> > --- > tools/perf/Documentation/perf-record.txt | 3 +++ > tools/perf/builtin-record.c | 18 +++++++++++++++--- > 2 files changed, 18 insertions(+), 3 deletions(-) > > diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt > index 5a626ef..3eea6de 100644 > --- a/tools/perf/Documentation/perf-record.txt > +++ b/tools/perf/Documentation/perf-record.txt > @@ -430,6 +430,9 @@ Configure all used events to run in user space. > --timestamp-filename > Append timestamp to output file name. > > +--timestamp-boundary:: > +Record timestamp boundary (time of first/last samples). > + > --switch-output[=mode]:: > Generate multiple perf.data files, timestamp prefixed, switching to a new one > based on 'mode' value: > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c > index f4d9fc5..082a0cb 100644 > --- a/tools/perf/builtin-record.c > +++ b/tools/perf/builtin-record.c > @@ -78,6 +78,7 @@ struct record { > bool no_buildid_cache_set; > bool buildid_all; > bool timestamp_filename; > + bool timestamp_boundary; > struct switch_output switch_output; > unsigned long long samples; > }; > @@ -391,8 +392,15 @@ static int process_sample_event(struct perf_tool *tool, > { > struct record *rec = container_of(tool, struct record, tool); > > - rec->samples++; > + if (rec->evlist->first_sample_time == 0) > + rec->evlist->first_sample_time = sample->time; > + > + rec->evlist->last_sample_time = sample->time; > > + if (rec->buildid_all) > + return 0; > + > + rec->samples++; > return build_id__mark_dso_hit(tool, event, sample, evsel, machine); > } > > @@ -417,9 +425,11 @@ static int process_buildids(struct record *rec) > > /* > * If --buildid-all is given, it marks all DSO regardless of hits, > - * so no need to process samples. > + * so no need to process samples. But if timestamp_boundary is enabled, > + * it still needs to walk on all samples to get the timestamps of > + * first/last samples. > */ > - if (rec->buildid_all) > + if (rec->buildid_all && !rec->timestamp_boundary) > rec->tool.sample = NULL; > > return perf_session__process_events(session); > @@ -1579,6 +1589,8 @@ static struct option __record_options[] = { > "Record build-id of all DSOs regardless of hits"), > OPT_BOOLEAN(0, "timestamp-filename", &record.timestamp_filename, > "append timestamp to output filename"), > + OPT_BOOLEAN(0, "timestamp-boundary", &record.timestamp_boundary, > + "Record timestamp boundary (time of first/last samples)"), > OPT_STRING_OPTARG_SET(0, "switch-output", &record.switch_output.str, > &record.switch_output.set, "signal,size,time", > "Switch output when receive SIGUSR2 or cross size,time threshold", > -- > 2.7.4
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