perf tools: Introduce timestamp__scnprintf_usec()

Joonwoo reported that there's a mismatch between timestamps in script
and sched commands. This was because of difference in printing the
timestamp. Factor out the code and share it so that they can be in
sync. Also I found that sched map has similar problem, fix it too.

Committer notes:

Fixed the max_lat_at bug introduced by Namhyung's original patch, as
pointed out by Joonwoo, and made it a function following the scnprintf()
model, i.e. returning the number of bytes formatted, and receiving as
the first parameter the object from where the data to the formatting is
obtained, renaming it from:

char *timestamp_in_usec(char *bf, size_t size, u64 timestamp)

to

int timestamp__scnprintf_usec(u64 timestamp, char *bf, size_t size)

Reported-by: Joonwoo Park <[e-mail]>
Signed-off-by: Namhyung Kim <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/builtin-sched.c

···
 	int i;
 	int ret;
 	u64 avg;
+	char max_lat_at[32];
 
 	if (!work_list->nb_atoms)
 		return;
···
 		printf(" ");
 
 	avg = work_list->total_lat / work_list->nb_atoms;
+	timestamp__scnprintf_usec(work_list->max_lat_at, max_lat_at, sizeof(max_lat_at));
 
-	printf("|%11.3f ms |%9" PRIu64 " | avg:%9.3f ms | max:%9.3f ms | max at: %13.6f s\n",
+	printf("|%11.3f ms |%9" PRIu64 " | avg:%9.3f ms | max:%9.3f ms | max at: %13s s\n",
 	      (double)work_list->total_runtime / NSEC_PER_MSEC,
 		 work_list->nb_atoms, (double)avg / NSEC_PER_MSEC,
 		 (double)work_list->max_lat / NSEC_PER_MSEC,
-		 (double)work_list->max_lat_at / NSEC_PER_SEC);
+		 max_lat_at);
 }
 
 static int pid_cmp(struct work_atoms *l, struct work_atoms *r)
···
 	int cpus_nr;
 	bool new_cpu = false;
 	const char *color = PERF_COLOR_NORMAL;
+	char stimestamp[32];
 
 	BUG_ON(this_cpu >= MAX_CPUS || this_cpu < 0);
 
···
 	if (sched->map.cpus && !cpu_map__has(sched->map.cpus, this_cpu))
 		goto out;
 
-	color_fprintf(stdout, color, "  %12.6f secs ", (double)timestamp / NSEC_PER_SEC);
+	timestamp__scnprintf_usec(timestamp, stimestamp, sizeof(stimestamp));
+	color_fprintf(stdout, color, "  %12s secs ", stimestamp);
 	if (new_shortname || (verbose && sched_in->tid)) {
 		const char *pid_color = color;
 

tools/perf/builtin-script.c

···
 {
 	struct perf_event_attr *attr = &evsel->attr;
 	unsigned long secs;
-	unsigned long usecs;
 	unsigned long long nsecs;
 
 	if (PRINT_FIELD(COMM)) {
···
 		nsecs = sample->time;
 		secs = nsecs / NSEC_PER_SEC;
 		nsecs -= secs * NSEC_PER_SEC;
-		usecs = nsecs / NSEC_PER_USEC;
+
 		if (nanosecs)
 			printf("%5lu.%09llu: ", secs, nsecs);
-		else
-			printf("%5lu.%06lu: ", secs, usecs);
+		else {
+			char sample_time[32];
+			timestamp__scnprintf_usec(sample->time, sample_time, sizeof(sample_time));
+			printf("%12s: ", sample_time);
+		}
 	}
 }
 

tools/perf/util/util.c

···
 	return 0;
 }
 
+int timestamp__scnprintf_usec(u64 timestamp, char *buf, size_t sz)
+{
+	u64  sec = timestamp / NSEC_PER_SEC;
+	u64 usec = (timestamp % NSEC_PER_SEC) / NSEC_PER_USEC;
+
+	return scnprintf(buf, sz, "%"PRIu64".%06"PRIu64, sec, usec);
+}
+
 unsigned long parse_tag_value(const char *str, struct parse_tag *tags)
 {
 	struct parse_tag *i = tags;

tools/perf/util/util.h

···
 #endif
 
 int is_printable_array(char *p, unsigned int len);
+
+int timestamp__scnprintf_usec(u64 timestamp, char *buf, size_t sz);
+
 #endif /* GIT_COMPAT_UTIL_H */