linux-kernel - [tip:perf/core] perf tools: Only override the default : tid comm entry

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Message-ID: <tip-a84808083688d82d7f1e5786ccf5df0ff7d448cb@git.kernel.org>
Date:	Wed, 19 Nov 2014 23:40:31 -0800
From:	tip-bot for Adrian Hunter <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	mingo@...nel.org, acme@...hat.com, fweisbec@...il.com,
	dsahern@...il.com, peterz@...radead.org,
	linux-kernel@...r.kernel.org, adrian.hunter@...el.com,
	jolsa@...hat.com, tglx@...utronix.de, eranian@...gle.com,
	paulus@...ba.org, hpa@...or.com, namhyung@...il.com
Subject: [tip:perf/core] perf tools: Only override the default :
 tid comm entry

Commit-ID:  a84808083688d82d7f1e5786ccf5df0ff7d448cb
Gitweb:     http://git.kernel.org/tip/a84808083688d82d7f1e5786ccf5df0ff7d448cb
Author:     Adrian Hunter <adrian.hunter@...el.com>
AuthorDate: Tue, 11 Nov 2014 16:16:41 +0200
Committer:  Arnaldo Carvalho de Melo <acme@...hat.com>
CommitDate: Wed, 19 Nov 2014 12:37:26 -0300

perf tools: Only override the default :tid comm entry

Events may still be ordered even if there are no timestamps e.g. if the
data is recorded per-thread.

Also synthesized COMM events have a timestamp of zero.

Consequently it is better to keep comm entries even if they have a
timestamp of zero.

However, when a struct thread is created the command string is not known
and a comm entry with a string of the form ":<tid>" is used.

In that case thread->comm_set is false and the comm entry should be
overridden.

Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
Cc: David Ahern <dsahern@...il.com>
Cc: Frederic Weisbecker <fweisbec@...il.com>
Cc: Jiri Olsa <jolsa@...hat.com>
Cc: Namhyung Kim <namhyung@...il.com>
Cc: Paul Mackerras <paulus@...ba.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Stephane Eranian <eranian@...gle.com>
Link: http://lkml.kernel.org/r/1415715423-15563-4-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 tools/perf/util/thread.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index a2157f0..9ebc8b1 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -103,15 +103,14 @@ struct comm *thread__exec_comm(const struct thread *thread)
 	return last;
 }
 
-/* CHECKME: time should always be 0 if event aren't ordered */
 int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp,
 		       bool exec)
 {
 	struct comm *new, *curr = thread__comm(thread);
 	int err;
 
-	/* Override latest entry if it had no specific time coverage */
-	if (!curr->start && !curr->exec) {
+	/* Override the default :tid entry */
+	if (!thread->comm_set) {
 		err = comm__override(curr, str, timestamp, exec);
 		if (err)
 			return err;
--
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