[tip:perf/core] perf tools: Don't stop synthesizing threads when one vanishes

[tip-bot for Arnaldo Carvalho de Melo]

Commit-ID:  ba361c92e73c771fcbbbd24c2c03c322e2de2e31
Gitweb:     http://git.kernel.org/tip/ba361c92e73c771fcbbbd24c2c03c322e2de2e31
Author:     Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate: Wed, 17 Oct 2012 18:50:13 -0300
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Thu, 25 Oct 2012 10:37:15 -0200

perf tools: Don't stop synthesizing threads when one vanishes

The perf_event__synthesize_threads routine synthesizes all the existing
threads in the system, because we don't have any kernel facilities to
ask for PERF_RECORD_{FORK,MMAP,COMM} for existing threads.

It was returning an error as soon as one thread couldn't be synthesized,
which is a bit extreme when, for instance, a forkish workload is
running, like a kernel compile.

Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-i7oas1eodpoer2bx38fwyasv@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/util/event.c |   13 ++++++-------
 1 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index 0ae444e..ca9ca28 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -405,16 +405,15 @@ int perf_event__synthesize_threads(struct perf_tool *tool,
 
 		if (*end) /* only interested in proper numerical dirents */
 			continue;
-
-		if (__event__synthesize_thread(comm_event, mmap_event, pid, 1,
-					   process, tool, machine) != 0) {
-			err = -1;
-			goto out_closedir;
-		}
+		/*
+ 		 * We may race with exiting thread, so don't stop just because
+ 		 * one thread couldn't be synthesized.
+ 		 */
+		__event__synthesize_thread(comm_event, mmap_event, pid, 1,
+					   process, tool, machine);
 	}
 
 	err = 0;
-out_closedir:
 	closedir(proc);
 out_free_mmap:
 	free(mmap_event);
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/