linux-kernel - [PATCH v5 2/6] perf record: Get the first sample time and last sample time

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Date:   Sat, 21 Oct 2017 07:27:50 +0800
From:   Jin Yao <yao.jin@...ux.intel.com>
To:     acme@...nel.org, jolsa@...nel.org, peterz@...radead.org,
        mingo@...hat.com, alexander.shishkin@...ux.intel.com
Cc:     Linux-kernel@...r.kernel.org, ak@...ux.intel.com,
        kan.liang@...el.com, yao.jin@...el.com,
        Jin Yao <yao.jin@...ux.intel.com>
Subject: [PATCH v5 2/6] perf record: Get the first sample time and last sample time

In perf record, it's walked on all samples yet. So it's very easy to get
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.

Change log:
-----------
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@...ux.intel.com>
---
 tools/perf/builtin-record.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index a6cbf16..bd711e8 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -391,8 +391,19 @@ 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 --buildid-all is given, it marks all DSO regardless of hits,
+	 * so no need to process this sample.
+	 */
+	if (rec->buildid_all)
+		return 0;
 
+	rec->samples++;
 	return build_id__mark_dso_hit(tool, event, sample, evsel, machine);
 }
 
@@ -415,13 +426,6 @@ static int process_buildids(struct record *rec)
 	 */
 	symbol_conf.ignore_vmlinux_buildid = true;
 
-	/*
-	 * If --buildid-all is given, it marks all DSO regardless of hits,
-	 * so no need to process samples.
-	 */
-	if (rec->buildid_all)
-		rec->tool.sample = NULL;
-
 	return perf_session__process_events(session);
 }
 
-- 
2.7.4