perf tools: change event inheritance logic in stat and record

By default, event inheritance across fork and pthread_create was on but the -i
option of stat and record, which enabled inheritance, led to believe it was off
by default.

This patch fixes this logic by inverting the meaning of the -i option.  By
default inheritance is on whether you attach to a process (-p), a thread (-t)
or start a process. If you pass -i, then you turn off inheritance. Turning off
inheritance if you don't need it, helps limit perf resource usage as well.

The patch also fixes perf stat -t xxxx and perf record -t xxxx which did not
start the counters.

Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <4bea9d2f.d60ce30a.0b5b.08e1@mx.google.com>
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 5 insertions, 5 deletions

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index e619ac89dff5..ff8c413b7e73 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -72,7 +72,7 @@ static unsigned int		nr_cpus				=  0;
 static int                      run_idx                         =  0;
 
 static int                      run_count                       =  1;
-static bool                     inherit                         =  true;
+static bool                     no_inherit                      = false;
 static bool                     scale                           =  true;
 static pid_t                    target_pid                      = -1;
 static pid_t                    target_tid                      = -1;
@@ -167,8 +167,8 @@ static int create_perf_stat_counter(int counter)
                                 ++ncreated;
                 }
         } else {
-                attr->inherit        = inherit;
-                if (target_pid == -1) {
+                attr->inherit = !no_inherit;
+                if (target_pid == -1 && target_tid == -1) {
                         attr->disabled = 1;
                         attr->enable_on_exec = 1;
                 }
@@ -518,8 +518,8 @@ static const struct option options[] = {
         OPT_CALLBACK('e', "event", NULL, "event",
                      "event selector. use 'perf list' to list available events",
                      parse_events),
-        OPT_BOOLEAN('i', "inherit", &inherit,
-                    "child tasks inherit counters"),
+        OPT_BOOLEAN('i', "no-inherit", &no_inherit,
+                    "child tasks do not inherit counters"),
         OPT_INTEGER('p', "pid", &target_pid,
                     "stat events on existing process id"),
         OPT_INTEGER('t', "tid", &target_tid,