perf stat: Add -o and --append options

This patch adds an option (-o) to save the output of perf stat into a
file. You could do this with perf record but not with perf stat.
Instead, you had to fiddle with stderr to save the counts into a
separate file.

The patch also adds the --append option so that results can be
concatenated into a single file across runs. Each run of the tool is
clearly separated by a comment line starting with a hash mark. The -A
option of perf record is already used by perf stat, so we only add a
long option.

$ perf stat -o res.txt date
$ cat res.txt

 Performance counter stats for 'date':

          0.791306 task-clock                #    0.668 CPUs utilized
                 2 context-switches          #    0.003 M/sec
                 0 CPU-migrations            #    0.000 M/sec
               197 page-faults               #    0.249 M/sec
           1878143 cycles                    #    2.373 GHz
   <not supported> stalled-cycles-frontend
   <not supported> stalled-cycles-backend
           1083367 instructions              #    0.58  insns per cycle
            193027 branches                  #  243.935 M/sec
              9014 branch-misses             #    4.67% of all branches

       0.001184746 seconds time elapsed

The option can be combined with -x to make the output file much easier
to parse.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20110815202233.GA18535@quad
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

3 files changed, 100 insertions, 64 deletions

diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt
index 918cc38ee6d1..08394c4879a8 100644
--- a/tools/perf/Documentation/perf-stat.txt
+++ b/tools/perf/Documentation/perf-stat.txt
@@ -94,6 +94,13 @@ an empty cgroup (monitor all the time) using, e.g., -G foo,,bar. Cgroups must ha
 corresponding events, i.e., they always refer to events defined earlier on the command
 line.
 
+-o file::
+-output file::
+Print the output into the designated file.
+
+--append::
+Append to the output file designated with the -o option. Ignored if -o is not specified.
+
 EXAMPLES
 --------
 
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 1ad04ce29c34..a22393d7ec6d 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -193,6 +193,8 @@ static int			big_num_opt			=  -1;
 static const char               *cpu_list;
 static const char               *csv_sep                        = NULL;
 static bool                     csv_output                      = false;
+static const char               *output_name                    = NULL;
+static FILE                     *output                         = NULL;
 
 static volatile int done = 0;
 
@@ -351,7 +353,7 @@ static int read_counter_aggr(struct perf_evsel *counter)
                 update_stats(&ps->res_stats[i], count[i]);
 
         if (verbose) {
-                fprintf(stderr, "%s: %" PRIu64 " %" PRIu64 " %" PRIu64 "\n",
+                fprintf(output, "%s: %" PRIu64 " %" PRIu64 " %" PRIu64 "\n",
                         event_name(counter), count[0], count[1], count[2]);
         }
 
@@ -518,9 +520,9 @@ static void print_noise_pct(double total, double avg)
                 pct = 100.0*total/avg;
 
         if (csv_output)
-                fprintf(stderr, "%s%.2f%%", csv_sep, pct);
+                fprintf(output, "%s%.2f%%", csv_sep, pct);
         else
-                fprintf(stderr, "  ( +-%6.2f%% )", pct);
+                fprintf(output, "  ( +-%6.2f%% )", pct);
 }
 
 static void print_noise(struct perf_evsel *evsel, double avg)
@@ -545,16 +547,17 @@ static void nsec_printout(int cpu, struct perf_evsel *evsel, double avg)
                         csv_output ? 0 : -4,
                         evsel_list->cpus->map[cpu], csv_sep);
 
-        fprintf(stderr, fmt, cpustr, msecs, csv_sep, event_name(evsel));
+        fprintf(output, fmt, cpustr, msecs, csv_sep, event_name(evsel));
 
         if (evsel->cgrp)
-                fprintf(stderr, "%s%s", csv_sep, evsel->cgrp->name);
+                fprintf(output, "%s%s", csv_sep, evsel->cgrp->name);
 
         if (csv_output)
                 return;
 
         if (perf_evsel__match(evsel, SOFTWARE, SW_TASK_CLOCK))
-                fprintf(stderr, " # %8.3f CPUs utilized          ", avg / avg_stats(&walltime_nsecs_stats));
+                fprintf(output, " # %8.3f CPUs utilized          ",
+                        avg / avg_stats(&walltime_nsecs_stats));
 }
 
 static void print_stalled_cycles_frontend(int cpu, struct perf_evsel *evsel __used, double avg)
@@ -575,9 +578,9 @@ static void print_stalled_cycles_frontend(int cpu, struct perf_evsel *evsel __us
         else if (ratio > 10.0)
                 color = PERF_COLOR_YELLOW;
 
-        fprintf(stderr, " #  ");
-        color_fprintf(stderr, color, "%6.2f%%", ratio);
-        fprintf(stderr, " frontend cycles idle   ");
+        fprintf(output, " #  ");
+        color_fprintf(output, color, "%6.2f%%", ratio);
+        fprintf(output, " frontend cycles idle   ");
 }
 
 static void print_stalled_cycles_backend(int cpu, struct perf_evsel *evsel __used, double avg)
@@ -598,9 +601,9 @@ static void print_stalled_cycles_backend(int cpu, struct perf_evsel *evsel __use
         else if (ratio > 20.0)
                 color = PERF_COLOR_YELLOW;
 
-        fprintf(stderr, " #  ");
-        color_fprintf(stderr, color, "%6.2f%%", ratio);
-        fprintf(stderr, " backend  cycles idle   ");
+        fprintf(output, " #  ");
+        color_fprintf(output, color, "%6.2f%%", ratio);
+        fprintf(output, " backend  cycles idle   ");
 }
 
 static void print_branch_misses(int cpu, struct perf_evsel *evsel __used, double avg)
@@ -621,9 +624,9 @@ static void print_branch_misses(int cpu, struct perf_evsel *evsel __used, double
         else if (ratio > 5.0)
                 color = PERF_COLOR_YELLOW;
 
-        fprintf(stderr, " #  ");
-        color_fprintf(stderr, color, "%6.2f%%", ratio);
-        fprintf(stderr, " of all branches        ");
+        fprintf(output, " #  ");
+        color_fprintf(output, color, "%6.2f%%", ratio);
+        fprintf(output, " of all branches        ");
 }
 
 static void print_l1_dcache_misses(int cpu, struct perf_evsel *evsel __used, double avg)
@@ -644,9 +647,9 @@ static void print_l1_dcache_misses(int cpu, struct perf_evsel *evsel __used, dou
         else if (ratio > 5.0)
                 color = PERF_COLOR_YELLOW;
 
-        fprintf(stderr, " #  ");
-        color_fprintf(stderr, color, "%6.2f%%", ratio);
-        fprintf(stderr, " of all L1-dcache hits  ");
+        fprintf(output, " #  ");
+        color_fprintf(output, color, "%6.2f%%", ratio);
+        fprintf(output, " of all L1-dcache hits  ");
 }
 
 static void print_l1_icache_misses(int cpu, struct perf_evsel *evsel __used, double avg)
@@ -667,9 +670,9 @@ static void print_l1_icache_misses(int cpu, struct perf_evsel *evsel __used, dou
         else if (ratio > 5.0)
                 color = PERF_COLOR_YELLOW;
 
-        fprintf(stderr, " #  ");
-        color_fprintf(stderr, color, "%6.2f%%", ratio);
-        fprintf(stderr, " of all L1-icache hits  ");
+        fprintf(output, " #  ");
+        color_fprintf(output, color, "%6.2f%%", ratio);
+        fprintf(output, " of all L1-icache hits  ");
 }
 
 static void print_dtlb_cache_misses(int cpu, struct perf_evsel *evsel __used, double avg)
@@ -690,9 +693,9 @@ static void print_dtlb_cache_misses(int cpu, struct perf_evsel *evsel __used, do
         else if (ratio > 5.0)
                 color = PERF_COLOR_YELLOW;
 
-        fprintf(stderr, " #  ");
-        color_fprintf(stderr, color, "%6.2f%%", ratio);
-        fprintf(stderr, " of all dTLB cache hits ");
+        fprintf(output, " #  ");
+        color_fprintf(output, color, "%6.2f%%", ratio);
+        fprintf(output, " of all dTLB cache hits ");
 }
 
 static void print_itlb_cache_misses(int cpu, struct perf_evsel *evsel __used, double avg)
@@ -713,9 +716,9 @@ static void print_itlb_cache_misses(int cpu, struct perf_evsel *evsel __used, do
         else if (ratio > 5.0)
                 color = PERF_COLOR_YELLOW;
 
-        fprintf(stderr, " #  ");
-        color_fprintf(stderr, color, "%6.2f%%", ratio);
-        fprintf(stderr, " of all iTLB cache hits ");
+        fprintf(output, " #  ");
+        color_fprintf(output, color, "%6.2f%%", ratio);
+        fprintf(output, " of all iTLB cache hits ");
 }
 
 static void print_ll_cache_misses(int cpu, struct perf_evsel *evsel __used, double avg)
@@ -736,9 +739,9 @@ static void print_ll_cache_misses(int cpu, struct perf_evsel *evsel __used, doub
         else if (ratio > 5.0)
                 color = PERF_COLOR_YELLOW;
 
-        fprintf(stderr, " #  ");
-        color_fprintf(stderr, color, "%6.2f%%", ratio);
-        fprintf(stderr, " of all LL-cache hits   ");
+        fprintf(output, " #  ");
+        color_fprintf(output, color, "%6.2f%%", ratio);
+        fprintf(output, " of all LL-cache hits   ");
 }
 
 static void abs_printout(int cpu, struct perf_evsel *evsel, double avg)
@@ -761,10 +764,10 @@ static void abs_printout(int cpu, struct perf_evsel *evsel, double avg)
         else
                 cpu = 0;
 
-        fprintf(stderr, fmt, cpustr, avg, csv_sep, event_name(evsel));
+        fprintf(output, fmt, cpustr, avg, csv_sep, event_name(evsel));
 
         if (evsel->cgrp)
-                fprintf(stderr, "%s%s", csv_sep, evsel->cgrp->name);
+                fprintf(output, "%s%s", csv_sep, evsel->cgrp->name);
 
         if (csv_output)
                 return;
@@ -775,14 +778,14 @@ static void abs_printout(int cpu, struct perf_evsel *evsel, double avg)
                 if (total)
                         ratio = avg / total;
 
-                fprintf(stderr, " #   %5.2f  insns per cycle        ", ratio);
+                fprintf(output, " #   %5.2f  insns per cycle        ", ratio);
 
                 total = avg_stats(&runtime_stalled_cycles_front_stats[cpu]);
                 total = max(total, avg_stats(&runtime_stalled_cycles_back_stats[cpu]));
 
                 if (total && avg) {
                         ratio = total / avg;
-                        fprintf(stderr, "\n                                             #   %5.2f  stalled cycles per insn", ratio);
+                        fprintf(output, "\n                                             #   %5.2f  stalled cycles per insn", ratio);
                 }
 
         } else if (perf_evsel__match(evsel, HARDWARE, HW_BRANCH_MISSES) &&
@@ -830,7 +833,7 @@ static void abs_printout(int cpu, struct perf_evsel *evsel, double avg)
                 if (total)
                         ratio = avg * 100 / total;
 
-                fprintf(stderr, " # %8.3f %% of all cache refs    ", ratio);
+                fprintf(output, " # %8.3f %% of all cache refs    ", ratio);
 
         } else if (perf_evsel__match(evsel, HARDWARE, HW_STALLED_CYCLES_FRONTEND)) {
                 print_stalled_cycles_frontend(cpu, evsel, avg);
@@ -842,16 +845,16 @@ static void abs_printout(int cpu, struct perf_evsel *evsel, double avg)
                 if (total)
                         ratio = 1.0 * avg / total;
 
-                fprintf(stderr, " # %8.3f GHz                    ", ratio);
+                fprintf(output, " # %8.3f GHz                    ", ratio);
         } else if (runtime_nsecs_stats[cpu].n != 0) {
                 total = avg_stats(&runtime_nsecs_stats[cpu]);
 
                 if (total)
                         ratio = 1000.0 * avg / total;
 
-                fprintf(stderr, " # %8.3f M/sec                  ", ratio);
+                fprintf(output, " # %8.3f M/sec                  ", ratio);
         } else {
-                fprintf(stderr, "                                   ");
+                fprintf(output, "                                   ");
         }
 }
 
@@ -866,7 +869,7 @@ static void print_counter_aggr(struct perf_evsel *counter)
         int scaled = counter->counts->scaled;
 
         if (scaled == -1) {
-                fprintf(stderr, "%*s%s%*s",
+                fprintf(output, "%*s%s%*s",
                         csv_output ? 0 : 18,
                         counter->supported ? CNTR_NOT_COUNTED : CNTR_NOT_SUPPORTED,
                         csv_sep,
@@ -874,9 +877,9 @@ static void print_counter_aggr(struct perf_evsel *counter)
                         event_name(counter));
 
                 if (counter->cgrp)
-                        fprintf(stderr, "%s%s", csv_sep, counter->cgrp->name);
+                        fprintf(output, "%s%s", csv_sep, counter->cgrp->name);
 
-                fputc('\n', stderr);
+                fputc('\n', output);
                 return;
         }
 
@@ -888,7 +891,7 @@ static void print_counter_aggr(struct perf_evsel *counter)
         print_noise(counter, avg);
 
         if (csv_output) {
-                fputc('\n', stderr);
+                fputc('\n', output);
                 return;
         }
 
@@ -898,9 +901,9 @@ static void print_counter_aggr(struct perf_evsel *counter)
                 avg_enabled = avg_stats(&ps->res_stats[1]);
                 avg_running = avg_stats(&ps->res_stats[2]);
 
-                fprintf(stderr, " [%5.2f%%]", 100 * avg_running / avg_enabled);
+                fprintf(output, " [%5.2f%%]", 100 * avg_running / avg_enabled);
         }
-        fprintf(stderr, "\n");
+        fprintf(output, "\n");
 }
 
 /*
@@ -917,7 +920,7 @@ static void print_counter(struct perf_evsel *counter)
                 ena = counter->counts->cpu[cpu].ena;
                 run = counter->counts->cpu[cpu].run;
                 if (run == 0 || ena == 0) {
-                        fprintf(stderr, "CPU%*d%s%*s%s%*s",
+                        fprintf(output, "CPU%*d%s%*s%s%*s",
                                 csv_output ? 0 : -4,
                                 evsel_list->cpus->map[cpu], csv_sep,
                                 csv_output ? 0 : 18,
@@ -927,9 +930,10 @@ static void print_counter(struct perf_evsel *counter)
                                 event_name(counter));
 
                         if (counter->cgrp)
-                                fprintf(stderr, "%s%s", csv_sep, counter->cgrp->name);
+                                fprintf(output, "%s%s",
+                                        csv_sep, counter->cgrp->name);
 
-                        fputc('\n', stderr);
+                        fputc('\n', output);
                         continue;
                 }
 
@@ -942,9 +946,10 @@ static void print_counter(struct perf_evsel *counter)
                         print_noise(counter, 1.0);
 
                         if (run != ena)
-                                fprintf(stderr, "  (%.2f%%)", 100.0 * run / ena);
+                                fprintf(output, "  (%.2f%%)",
+                                        100.0 * run / ena);
                 }
-                fputc('\n', stderr);
+                fputc('\n', output);
         }
 }
 
@@ -956,21 +961,21 @@ static void print_stat(int argc, const char **argv)
         fflush(stdout);
 
         if (!csv_output) {
-                fprintf(stderr, "\n");
-                fprintf(stderr, " Performance counter stats for ");
+                fprintf(output, "\n");
+                fprintf(output, " Performance counter stats for ");
                 if(target_pid == -1 && target_tid == -1) {
-                        fprintf(stderr, "\'%s", argv[0]);
+                        fprintf(output, "\'%s", argv[0]);
                         for (i = 1; i < argc; i++)
-                                fprintf(stderr, " %s", argv[i]);
+                                fprintf(output, " %s", argv[i]);
                 } else if (target_pid != -1)
-                        fprintf(stderr, "process id \'%d", target_pid);
+                        fprintf(output, "process id \'%d", target_pid);
                 else
-                        fprintf(stderr, "thread id \'%d", target_tid);
+                        fprintf(output, "thread id \'%d", target_tid);
 
-                fprintf(stderr, "\'");
+                fprintf(output, "\'");
                 if (run_count > 1)
-                        fprintf(stderr, " (%d runs)", run_count);
-                fprintf(stderr, ":\n\n");
+                        fprintf(output, " (%d runs)", run_count);
+                fprintf(output, ":\n\n");
         }
 
         if (no_aggr) {
@@ -983,15 +988,15 @@ static void print_stat(int argc, const char **argv)
 
         if (!csv_output) {
                 if (!null_run)
-                        fprintf(stderr, "\n");
-                fprintf(stderr, " %17.9f seconds time elapsed",
+                        fprintf(output, "\n");
+                fprintf(output, " %17.9f seconds time elapsed",
                                 avg_stats(&walltime_nsecs_stats)/1e9);
                 if (run_count > 1) {
-                        fprintf(stderr, "                                        ");
+                        fprintf(output, "                                        ");
                         print_noise_pct(stddev_stats(&walltime_nsecs_stats),
                                         avg_stats(&walltime_nsecs_stats));
                 }
-                fprintf(stderr, "\n\n");
+                fprintf(output, "\n\n");
         }
 }
 
@@ -1029,6 +1034,8 @@ static int stat__set_big_num(const struct option *opt __used,
         return 0;
 }
 
+static bool append_file;
+
 static const struct option options[] = {
         OPT_CALLBACK('e', "event", &evsel_list, "event",
                      "event selector. use 'perf list' to list available events",
@@ -1067,6 +1074,9 @@ static const struct option options[] = {
         OPT_CALLBACK('G', "cgroup", &evsel_list, "name",
                      "monitor event in cgroup name only",
                      parse_cgroups),
+        OPT_STRING('o', "output", &output_name, "file",
+                    "output file name"),
+        OPT_BOOLEAN(0, "append", &append_file, "append to the output file"),
         OPT_END()
 };
 
@@ -1138,6 +1148,7 @@ int cmd_stat(int argc, const char **argv, const char *prefix __used)
 {
         struct perf_evsel *pos;
         int status = -ENOMEM;
+        const char *mode;
 
         setlocale(LC_ALL, "");
 
@@ -1148,6 +1159,23 @@ int cmd_stat(int argc, const char **argv, const char *prefix __used)
         argc = parse_options(argc, argv, options, stat_usage,
                 PARSE_OPT_STOP_AT_NON_OPTION);
 
+        output = stderr;
+        if (output_name && strcmp(output_name, "-"))
+                output = NULL;
+
+        if (!output) {
+                struct timespec tm;
+                mode = append_file ? "a" : "w";
+
+                output = fopen(output_name, mode);
+                if (!output) {
+                        perror("failed to create output file");
+                        exit(-1);
+                }
+                clock_gettime(CLOCK_REALTIME, &tm);
+                fprintf(output, "# started on %s\n", ctime(&tm.tv_sec));
+        }
+
         if (csv_sep)
                 csv_output = true;
         else
@@ -1223,7 +1251,8 @@ int cmd_stat(int argc, const char **argv, const char *prefix __used)
         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(output, "[ perf stat: executing run #%d ... ]\n",
+                                run_idx + 1);
 
                 if (sync_run)
                         sync();
diff --git a/tools/perf/util/color.c b/tools/perf/util/color.c
index e191eb9a667f..521c38a79190 100644
--- a/tools/perf/util/color.c
+++ b/tools/perf/util/color.c
@@ -200,7 +200,7 @@ static int __color_vfprintf(FILE *fp, const char *color, const char *fmt,
          * Auto-detect:
          */
         if (perf_use_color_default < 0) {
-                if (isatty(1) || pager_in_use())
+                if (isatty(fileno(fp)) || pager_in_use())
                         perf_use_color_default = 1;
                 else
                         perf_use_color_default = 0;