perf evlist: Fix side band thread draining

Current perf_evlist__poll_thread() code could finish without draining
the data. Adding the logic that makes sure we won't finish before the
drain.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Fixes: ccc6a592ad1b ("perf evlist: Introduce side band thread")
Link: http://lkml.kernel.org/r/20190416160127.30203-9-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 6689378ee577c18ca1efac4b95f84c5c45d40404..51ead577533fa6f6ee8c8cc49b8fc084490f0ef1 100644 (file)
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -1868,12 +1868,12 @@ static void *perf_evlist__poll_thread(void *arg)
 {
        struct perf_evlist *evlist = arg;
        bool draining = false;
-       int i;
+       int i, done = 0;
+
+       while (!done) {
+               bool got_data = false;
 
-       while (draining || !(evlist->thread.done)) {
-               if (draining)
-                       draining = false;
-               else if (evlist->thread.done)
+               if (evlist->thread.done)
                        draining = true;
 
                if (!draining)
@@ -1894,9 +1894,13 @@ static void *perf_evlist__poll_thread(void *arg)
                                        pr_warning("cannot locate proper evsel for the side band event\n");
 
                                perf_mmap__consume(map);
+                               got_data = true;
                        }
                        perf_mmap__read_done(map);
                }
+
+               if (draining && !got_data)
+                       break;
        }
        return NULL;
 }