perf tools: Add an option to multiplex counters in a single channel
Add an option to multiplex counters output in the channel of
the group leader, ie: the first counter opened:
-M --multiplex
The effect is better serialized samples. This is especially
useful for tracepoint samples that need to be well serialized
for their post-processing.
Also make use of this option in 'perf sched'.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 99a12fe..79f99db 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -48,6 +48,7 @@
static int inherit_stat = 0;
static int no_samples = 0;
static int sample_address = 0;
+static int multiplex = 0;
static long samples;
static struct timeval last_read;
@@ -485,6 +486,9 @@
exit(-1);
}
+ if (multiplex && fd[nr_cpu][counter] != group_fd)
+ ioctl(fd[nr_cpu][counter], PERF_COUNTER_IOC_SET_OUTPUT, group_fd);
+
ioctl(fd[nr_cpu][counter], PERF_COUNTER_IOC_ENABLE);
}
@@ -681,6 +685,8 @@
"Sample addresses"),
OPT_BOOLEAN('n', "no-samples", &no_samples,
"don't sample"),
+ OPT_BOOLEAN('M', "multiplex", &multiplex,
+ "multiplex counter output in a single channel"),
OPT_END()
};