[PATCH] perf: add -o and --append options to perf stat

[Stephane Eranian <eranian@google.com>]

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
# started on Mon Aug 15 19:46:55 2011


 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.

Signed-off-by: Stephane Eranian <eranian@google.com>
---

diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt
index 918cc38..08394c4 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 1ad04ce..a22393d 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 e191eb9..521c38a 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;