perf debug: Add debug_set_display_time function

Allow to display time in perf debug output via new
debug_set_display_time function.

It will be used in perf daemon command to get verbose output into log
file.

The debug time format is:

  [2020-12-03 18:25:31.822152] affinity: SYS
  [2020-12-03 18:25:31.822164] mmap flush: 1
  [2020-12-03 18:25:31.822175] comp level: 0
  [2020-12-03 18:25:32.002047] mmap size 528384B

Committer notes:

Cast tod.tv_usec to long to avoid this problem:

    78    12.70 ubuntu:18.04-x-sparc64        : FAIL sparc64-linux-gnu-gcc (Ubuntu 7.5.0-3ubuntu1~18.04) 7.5.0

  util/debug.c: In function 'fprintf_time':
  util/debug.c:63:32: error: format '%lu' expects argument of type 'long unsigned int', but argument 4 has type '__suseconds_t {aka int}' [-Werror=format=]
    return fprintf(file, "[%s.%06lu] ", date, tod.tv_usec);
                              ~~~~^           ~~~~~~~~~~~
                              %06u
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Budankov <abudankov@huawei.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20210102220441.794923-4-jolsa@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/debug.c

@@ -10,6 +10,7 @@
 #include <api/debug.h>
 #include <linux/kernel.h>
 #include <linux/time64.h>
+#include <sys/time.h>
 #ifdef HAVE_BACKTRACE_SUPPORT
 #include <execinfo.h>
 #endif
@@ -31,21 +32,48 @@ int debug_ordered_events;
 static int redirect_to_stderr;
 int debug_data_convert;
 static FILE *debug_file;
+bool debug_display_time;
 
 void debug_set_file(FILE *file)
 {
 	debug_file = file;
 }
 
+void debug_set_display_time(bool set)
+{
+	debug_display_time = set;
+}
+
+static int fprintf_time(FILE *file)
+{
+	struct timeval tod;
+	struct tm ltime;
+	char date[64];
+
+	if (!debug_display_time)
+		return 0;
+
+	if (gettimeofday(&tod, NULL) != 0)
+		return 0;
+
+	if (localtime_r(&tod.tv_sec, &ltime) == NULL)
+		return 0;
+
+	strftime(date, sizeof(date),  "%F %H:%M:%S", &ltime);
+	return fprintf(file, "[%s.%06lu] ", date, (long)tod.tv_usec);
+}
+
 int veprintf(int level, int var, const char *fmt, va_list args)
 {
 	int ret = 0;
 
 	if (var >= level) {
-		if (use_browser >= 1 && !redirect_to_stderr)
+		if (use_browser >= 1 && !redirect_to_stderr) {
 			ui_helpline__vshow(fmt, args);
-		else
-			ret = vfprintf(debug_file, fmt, args);
+		} else {
+			ret = fprintf_time(debug_file);
+			ret += vfprintf(debug_file, fmt, args);
+		}
 	}
 
 	return ret;

tools/perf/util/debug.h

@@ -64,6 +64,7 @@ int veprintf(int level, int var, const char *fmt, va_list args);
 
 int perf_debug_option(const char *str);
 void debug_set_file(FILE *file);
+void debug_set_display_time(bool set);
 void perf_debug_setup(void);
 int perf_quiet_option(void);