perf record: Disable profiling before draining the buffer

I noticed that perf-record continues profiling itself after the
child terminated and we're draining the buffer.

This can cause a _lot_ of overhead with --all recording - we keep
and keep recording, which produces new and new events.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 5f3127e7a6150e778a5823c2b0509744fd35902e..2459e5a22ed88125655496c141ff396b6970b57e 100644 (file)
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -524,6 +524,7 @@ static int __cmd_record(int argc, const char **argv)
        pid_t pid = 0;
        int flags;
        int ret;
+       unsigned long waking = 0;
 
        page_size = sysconf(_SC_PAGE_SIZE);
        nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
@@ -634,10 +635,20 @@ static int __cmd_record(int argc, const char **argv)
                if (hits == samples) {
                        if (done)
                                break;
-                       ret = poll(event_array, nr_poll, 100);
+                       ret = poll(event_array, nr_poll, -1);
+                       waking++;
+               }
+
+               if (done) {
+                       for (i = 0; i < nr_cpu; i++) {
+                               for (counter = 0; counter < nr_counters; counter++)
+                                       ioctl(fd[i][counter], PERF_COUNTER_IOC_DISABLE);
+                       }
                }
        }
 
+       fprintf(stderr, "[ perf record: Woken up %ld times to write data ]\n", waking);
+
        /*
         * Approximate RIP event size: 24 bytes.
         */