perf stat: Add --pre and --post command

In order to measure kernel builds, one has to do some pre/post cleanup
work in order to do the repeat build.

So provide --pre and --post command hooks to allow doing just that.

  perf stat --repeat 10 --null --sync --pre 'make -s O=defconfig-build/clean' \
	-- make -s -j64 O=defconfig-build/ bzImage

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Stephane Eranian <eranian@gmail.com>
Link: http://lkml.kernel.org/r/1350992414.13456.5.camel@twins
[ committer note: Added respective entries in Documentation/perf-stat.txt ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 36 insertions, 6 deletions

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 93b9011fa3e2..6888960ef8b8 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -57,6 +57,7 @@
 #include "util/thread.h"
 #include "util/thread_map.h"
 
+#include <stdlib.h>
 #include <sys/prctl.h>
 #include <locale.h>
 
@@ -83,6 +84,9 @@ static const char		*csv_sep			= NULL;
 static bool                     csv_output                      = false;
 static bool                     group                           = false;
 static FILE                     *output                         = NULL;
+static const char               *pre_cmd                        = NULL;
+static const char               *post_cmd                       = NULL;
+static bool                     sync_run                        = false;
 
 static volatile int done = 0;
 
@@ -265,7 +269,7 @@ static int read_counter(struct perf_evsel *counter)
         return 0;
 }
 
-static int run_perf_stat(int argc __maybe_unused, const char **argv)
+static int __run_perf_stat(int argc __maybe_unused, const char **argv)
 {
         unsigned long long t0, t1;
         struct perf_evsel *counter, *first;
@@ -405,6 +409,32 @@ static int run_perf_stat(int argc __maybe_unused, const char **argv)
         return WEXITSTATUS(status);
 }
 
+static int run_perf_stat(int argc __maybe_unused, const char **argv)
+{
+        int ret;
+
+        if (pre_cmd) {
+                ret = system(pre_cmd);
+                if (ret)
+                        return ret;
+        }
+
+        if (sync_run)
+                sync();
+
+        ret = __run_perf_stat(argc, argv);
+        if (ret)
+                return ret;
+
+        if (post_cmd) {
+                ret = system(post_cmd);
+                if (ret)
+                        return ret;
+        }
+
+        return ret;
+}
+
 static void print_noise_pct(double total, double avg)
 {
         double pct = rel_stddev_stats(total, avg);
@@ -1069,8 +1099,7 @@ static int add_default_attributes(void)
 
 int cmd_stat(int argc, const char **argv, const char *prefix __maybe_unused)
 {
-        bool append_file = false,
-             sync_run = false;
+        bool append_file = false;
         int output_fd = 0;
         const char *output_name = NULL;
         const struct option options[] = {
@@ -1114,6 +1143,10 @@ int cmd_stat(int argc, const char **argv, const char *prefix __maybe_unused)
         OPT_BOOLEAN(0, "append", &append_file, "append to the output file"),
         OPT_INTEGER(0, "log-fd", &output_fd,
                     "log output to fd, instead of stderr"),
+        OPT_STRING(0, "pre", &pre_cmd, "command",
+                        "command to run prior to the measured command"),
+        OPT_STRING(0, "post", &post_cmd, "command",
+                        "command to run after to the measured command"),
         OPT_END()
         };
         const char * const stat_usage[] = {
@@ -1238,9 +1271,6 @@ int cmd_stat(int argc, const char **argv, const char *prefix __maybe_unused)
                         fprintf(output, "[ perf stat: executing run #%d ... ]\n",
                                 run_idx + 1);
 
-                if (sync_run)
-                        sync();
-
                 status = run_perf_stat(argc, argv);
         }