1 files changed, 102 insertions, 69 deletions

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 6d3eeac1ea25..2e03524a1de0 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -32,6 +32,7 @@
  *   Wu Fengguang <fengguang.wu@intel.com>
  *   Mike Galbraith <efault@gmx.de>
  *   Paul Mackerras <paulus@samba.org>
+ *   Jaswinder Singh Rajput <jaswinder@kernel.org>
  *
  * Released under the GPL v2. (and only v2, not any later version)
  */
@@ -45,7 +46,7 @@
 #include <sys/prctl.h>
 #include <math.h>
 
-static struct perf_counter_attr default_attrs[MAX_COUNTERS] = {
+static struct perf_counter_attr default_attrs[] = {
 
   { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_TASK_CLOCK      },
   { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_CONTEXT_SWITCHES},
@@ -59,42 +60,28 @@ static struct perf_counter_attr default_attrs[MAX_COUNTERS] = {
 
 };
 
+#define MAX_RUN                 100
+
 static int                      system_wide                     =  0;
-static int                      inherit                         =  1;
 static int                      verbose                         =  0;
-
-static int                      fd[MAX_NR_CPUS][MAX_COUNTERS];
-
-static int                      target_pid                      = -1;
 static int                      nr_cpus                         =  0;
-static unsigned int             page_size;
+static int                      run_idx                         =  0;
 
+static int                      run_count                       =  1;
+static int                      inherit                         =  1;
 static int                      scale                           =  1;
+static int                      target_pid                      = -1;
+static int                      null_run                        =  0;
 
-static const unsigned int default_count[] = {
-        1000000,
-        1000000,
-          10000,
-          10000,
-        1000000,
-          10000,
-};
-
-#define MAX_RUN 100
-
-static int                      run_count               =  1;
-static int                      run_idx                 =  0;
-
-static u64                      event_res[MAX_RUN][MAX_COUNTERS][3];
-static u64                      event_scaled[MAX_RUN][MAX_COUNTERS];
-
-//static u64                    event_hist[MAX_RUN][MAX_COUNTERS][3];
-
+static int                      fd[MAX_NR_CPUS][MAX_COUNTERS];
 
 static u64                      runtime_nsecs[MAX_RUN];
 static u64                      walltime_nsecs[MAX_RUN];
 static u64                      runtime_cycles[MAX_RUN];
 
+static u64                      event_res[MAX_RUN][MAX_COUNTERS][3];
+static u64                      event_scaled[MAX_RUN][MAX_COUNTERS];
+
 static u64                      event_res_avg[MAX_COUNTERS][3];
 static u64                      event_res_noise[MAX_COUNTERS][3];
 
@@ -109,7 +96,10 @@ static u64			walltime_nsecs_noise;
 static u64                      runtime_cycles_avg;
 static u64                      runtime_cycles_noise;
 
-static void create_perf_stat_counter(int counter)
+#define ERR_PERF_OPEN \
+"Error: counter %d, sys_perf_counter_open() syscall returned with %d (%s)\n"
+
+static void create_perf_stat_counter(int counter, int pid)
 {
         struct perf_counter_attr *attr = attrs + counter;
 
@@ -119,20 +109,21 @@ static void create_perf_stat_counter(int counter)
 
         if (system_wide) {
                 int cpu;
-                for (cpu = 0; cpu < nr_cpus; cpu ++) {
+                for (cpu = 0; cpu < nr_cpus; cpu++) {
                         fd[cpu][counter] = sys_perf_counter_open(attr, -1, cpu, -1, 0);
-                        if (fd[cpu][counter] < 0 && verbose) {
-                                printf("Error: counter %d, sys_perf_counter_open() syscall returned with %d (%s)\n", counter, fd[cpu][counter], strerror(errno));
-                        }
+                        if (fd[cpu][counter] < 0 && verbose)
+                                fprintf(stderr, ERR_PERF_OPEN, counter,
+                                        fd[cpu][counter], strerror(errno));
                 }
         } else {
-                attr->inherit   = inherit;
-                attr->disabled  = 1;
-
-                fd[0][counter] = sys_perf_counter_open(attr, 0, -1, -1, 0);
-                if (fd[0][counter] < 0 && verbose) {
-                        printf("Error: counter %d, sys_perf_counter_open() syscall returned with %d (%s)\n", counter, fd[0][counter], strerror(errno));
-                }
+                attr->inherit        = inherit;
+                attr->disabled       = 1;
+                attr->enable_on_exec = 1;
+
+                fd[0][counter] = sys_perf_counter_open(attr, pid, -1, -1, 0);
+                if (fd[0][counter] < 0 && verbose)
+                        fprintf(stderr, ERR_PERF_OPEN, counter,
+                                fd[0][counter], strerror(errno));
         }
 }
 
@@ -168,7 +159,7 @@ static void read_counter(int counter)
         count[0] = count[1] = count[2] = 0;
 
         nv = scale ? 3 : 1;
-        for (cpu = 0; cpu < nr_cpus; cpu ++) {
+        for (cpu = 0; cpu < nr_cpus; cpu++) {
                 if (fd[cpu][counter] < 0)
                         continue;
 
@@ -215,32 +206,67 @@ static int run_perf_stat(int argc, const char **argv)
         int status = 0;
         int counter;
         int pid;
+        int child_ready_pipe[2], go_pipe[2];
+        char buf;
 
         if (!system_wide)
                 nr_cpus = 1;
 
-        for (counter = 0; counter < nr_counters; counter++)
-                create_perf_stat_counter(counter);
-
-        /*
-         * Enable counters and exec the command:
-         */
-        t0 = rdclock();
-        prctl(PR_TASK_PERF_COUNTERS_ENABLE);
+        if (pipe(child_ready_pipe) < 0 || pipe(go_pipe) < 0) {
+                perror("failed to create pipes");
+                exit(1);
+        }
 
         if ((pid = fork()) < 0)
                 perror("failed to fork");
 
         if (!pid) {
-                if (execvp(argv[0], (char **)argv)) {
-                        perror(argv[0]);
-                        exit(-1);
-                }
+                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.
+                 */
+                read(go_pipe[0], &buf, 1);
+
+                execvp(argv[0], (char **)argv);
+
+                perror(argv[0]);
+                exit(-1);
         }
 
+        /*
+         * Wait for the child to be ready to exec.
+         */
+        close(child_ready_pipe[1]);
+        close(go_pipe[0]);
+        read(child_ready_pipe[0], &buf, 1);
+        close(child_ready_pipe[0]);
+
+        for (counter = 0; counter < nr_counters; counter++)
+                create_perf_stat_counter(counter, pid);
+
+        /*
+         * Enable counters and exec the command:
+         */
+        t0 = rdclock();
+
+        close(go_pipe[1]);
         wait(&status);
 
-        prctl(PR_TASK_PERF_COUNTERS_DISABLE);
         t1 = rdclock();
 
         walltime_nsecs[run_idx] = t1 - t0;
@@ -262,7 +288,7 @@ static void nsec_printout(int counter, u64 *count, u64 *noise)
 {
         double msecs = (double)count[0] / 1000000;
 
-        fprintf(stderr, " %14.6f  %-20s", msecs, event_name(counter));
+        fprintf(stderr, " %14.6f  %-24s", msecs, event_name(counter));
 
         if (attrs[counter].type == PERF_TYPE_SOFTWARE &&
                 attrs[counter].config == PERF_COUNT_SW_TASK_CLOCK) {
@@ -276,7 +302,7 @@ static void nsec_printout(int counter, u64 *count, u64 *noise)
 
 static void abs_printout(int counter, u64 *count, u64 *noise)
 {
-        fprintf(stderr, " %14Ld  %-20s", count[0], event_name(counter));
+        fprintf(stderr, " %14Ld  %-24s", count[0], event_name(counter));
 
         if (runtime_cycles_avg &&
                 attrs[counter].type == PERF_TYPE_HARDWARE &&
@@ -306,7 +332,7 @@ static void print_counter(int counter)
         scaled = event_scaled_avg[counter];
 
         if (scaled == -1) {
-                fprintf(stderr, " %14s  %-20s\n",
+                fprintf(stderr, " %14s  %-24s\n",
                         "<not counted>", event_name(counter));
                 return;
         }
@@ -364,8 +390,11 @@ static void calc_avg(void)
                                 event_res_avg[j]+1, event_res[i][j]+1);
                         update_avg("counter/2", j,
                                 event_res_avg[j]+2, event_res[i][j]+2);
-                        update_avg("scaled", j,
-                                event_scaled_avg + j, event_scaled[i]+j);
+                        if (event_scaled[i][j] != -1)
+                                update_avg("scaled", j,
+                                        event_scaled_avg + j, event_scaled[i]+j);
+                        else
+                                event_scaled_avg[j] = -1;
                 }
         }
         runtime_nsecs_avg /= run_count;
@@ -429,11 +458,14 @@ static void print_stat(int argc, const char **argv)
         for (counter = 0; counter < nr_counters; counter++)
                 print_counter(counter);
 
-
         fprintf(stderr, "\n");
-        fprintf(stderr, " %14.9f  seconds time elapsed.\n",
+        fprintf(stderr, " %14.9f  seconds time elapsed",
                         (double)walltime_nsecs_avg/1e9);
-        fprintf(stderr, "\n");
+        if (run_count > 1) {
+                fprintf(stderr, "   ( +- %7.3f%% )",
+                        100.0*(double)walltime_nsecs_noise/(double)walltime_nsecs_avg);
+        }
+        fprintf(stderr, "\n\n");
 }
 
 static volatile int signr = -1;
@@ -466,13 +498,15 @@ static const struct option options[] = {
         OPT_INTEGER('p', "pid", &target_pid,
                     "stat events on existing pid"),
         OPT_BOOLEAN('a', "all-cpus", &system_wide,
-                            "system-wide collection from all CPUs"),
+                    "system-wide collection from all CPUs"),
         OPT_BOOLEAN('S', "scale", &scale,
-                            "scale/normalize counters"),
+                    "scale/normalize counters"),
         OPT_BOOLEAN('v', "verbose", &verbose,
                     "be more verbose (show counter open errors, etc)"),
         OPT_INTEGER('r', "repeat", &run_count,
                     "repeat command and print average + stddev (max: 100)"),
+        OPT_BOOLEAN('n', "null", &null_run,
+                    "null run - dont start any counters"),
         OPT_END()
 };
 
@@ -480,18 +514,17 @@ int cmd_stat(int argc, const char **argv, const char *prefix)
 {
         int status;
 
-        page_size = sysconf(_SC_PAGE_SIZE);
-
-        memcpy(attrs, default_attrs, sizeof(attrs));
-
         argc = parse_options(argc, argv, options, stat_usage, 0);
         if (!argc)
                 usage_with_options(stat_usage, options);
         if (run_count <= 0 || run_count > MAX_RUN)
                 usage_with_options(stat_usage, options);
 
-        if (!nr_counters)
-                nr_counters = 8;
+        /* Set attrs and nr_counters if no event is selected and !null_run */
+        if (!null_run && !nr_counters) {
+                memcpy(attrs, default_attrs, sizeof(default_attrs));
+                nr_counters = ARRAY_SIZE(default_attrs);
+        }
 
         nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
         assert(nr_cpus <= MAX_NR_CPUS);
@@ -511,7 +544,7 @@ int cmd_stat(int argc, const char **argv, const char *prefix)
         status = 0;
         for (run_idx = 0; run_idx < run_count; run_idx++) {
                 if (run_count != 1 && verbose)
-                        fprintf(stderr, "[ perf stat: executing run #%d ... ]\n", run_idx+1);
+                        fprintf(stderr, "[ perf stat: executing run #%d ... ]\n", run_idx + 1);
                 status = run_perf_stat(argc, argv);
         }