perf stat: Use perf_evlist__prepare/start_workload()

The perf stat had an open code to the duplicated work.  Use the helper
as it now can be called without struct perf_record_opts.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1362987798-24969-7-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 7 insertions, 51 deletions

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 20ffaf98782e..69fe6ed89627 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -337,16 +337,14 @@ static void print_interval(void)
         }
 }
 
-static int __run_perf_stat(int argc __maybe_unused, const char **argv)
+static int __run_perf_stat(int argc, const char **argv)
 {
         char msg[512];
         unsigned long long t0, t1;
         struct perf_evsel *counter;
         struct timespec ts;
         int status = 0;
-        int child_ready_pipe[2], go_pipe[2];
         const bool forks = (argc > 0);
-        char buf;
 
         if (interval) {
                 ts.tv_sec  = interval / 1000;
@@ -362,55 +360,12 @@ static int __run_perf_stat(int argc __maybe_unused, const char **argv)
                 return -1;
         }
 
-        if (forks && (pipe(child_ready_pipe) < 0 || pipe(go_pipe) < 0)) {
-                perror("failed to create pipes");
-                return -1;
-        }
-
         if (forks) {
-                if ((child_pid = fork()) < 0)
-                        perror("failed to fork");
-
-                if (!child_pid) {
-                        close(child_ready_pipe[0]);
-                        close(go_pipe[1]);
-                        fcntl(go_pipe[0], F_SETFD, FD_CLOEXEC);
-
-                        /*
-                         * Do a dummy execvp to get the PLT entry resolved,
-                         * so we avoid the resolver overhead on the real
-                         * execvp call.
-                         */
-                        execvp("", (char **)argv);
-
-                        /*
-                         * Tell the parent we're ready to go
-                         */
-                        close(child_ready_pipe[1]);
-
-                        /*
-                         * Wait until the parent tells us to go.
-                         */
-                        if (read(go_pipe[0], &buf, 1) == -1)
-                                perror("unable to read pipe");
-
-                        execvp(argv[0], (char **)argv);
-
-                        perror(argv[0]);
-                        exit(-1);
+                if (perf_evlist__prepare_workload(evsel_list, &target, argv,
+                                                  false, false) < 0) {
+                        perror("failed to prepare workload");
+                        return -1;
                 }
-
-                if (perf_target__none(&target))
-                        evsel_list->threads->map[0] = child_pid;
-
-                /*
-                 * Wait for the child to be ready to exec.
-                 */
-                close(child_ready_pipe[1]);
-                close(go_pipe[0]);
-                if (read(child_ready_pipe[0], &buf, 1) == -1)
-                        perror("unable to read pipe");
-                close(child_ready_pipe[0]);
         }
 
         if (group)
@@ -457,7 +412,8 @@ static int __run_perf_stat(int argc __maybe_unused, const char **argv)
         clock_gettime(CLOCK_MONOTONIC, &ref_time);
 
         if (forks) {
-                close(go_pipe[1]);
+                perf_evlist__start_workload(evsel_list);
+
                 if (interval) {
                         while (!waitpid(child_pid, &status, WNOHANG)) {
                                 nanosleep(&ts, NULL);