perf record: Add clockid parameter

Teach perf-record about the new perf_event_attr::{use_clockid, clockid}
fields. Add a simple parameter to set the clock (if any) to be used for
the events to be recorded into the data file.

Since we store the entire perf_event_attr in the EVENT_DESC section we
also already store the used clockid in the data file.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yunlong Song <yunlong.song@huawei.com>
Link: http://lkml.kernel.org/r/20150407154851.GR23123@twins.programming.kicks-ass.net
[ Conditionally define CLOCK_BOOTTIME, at least rhel6 doesn't have it - dsahern
  Ditto for CLOCK_MONOTONIC_RAW, sles11sp2 doesn't have it - yunlong.song ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-record.c

@@ -711,6 +711,90 @@ static int perf_record_config(const char *var, const char *value, void *cb)
 	return perf_default_config(var, value, cb);
 }
 
+struct clockid_map {
+	const char *name;
+	int clockid;
+};
+
+#define CLOCKID_MAP(n, c)	\
+	{ .name = n, .clockid = (c), }
+
+#define CLOCKID_END	{ .name = NULL, }
+
+
+/*
+ * Add the missing ones, we need to build on many distros...
+ */
+#ifndef CLOCK_MONOTONIC_RAW
+#define CLOCK_MONOTONIC_RAW 4
+#endif
+#ifndef CLOCK_BOOTTIME
+#define CLOCK_BOOTTIME 7
+#endif
+#ifndef CLOCK_TAI
+#define CLOCK_TAI 11
+#endif
+
+static const struct clockid_map clockids[] = {
+	/* available for all events, NMI safe */
+	CLOCKID_MAP("monotonic", CLOCK_MONOTONIC),
+	CLOCKID_MAP("monotonic_raw", CLOCK_MONOTONIC_RAW),
+
+	/* available for some events */
+	CLOCKID_MAP("realtime", CLOCK_REALTIME),
+	CLOCKID_MAP("boottime", CLOCK_BOOTTIME),
+	CLOCKID_MAP("tai", CLOCK_TAI),
+
+	/* available for the lazy */
+	CLOCKID_MAP("mono", CLOCK_MONOTONIC),
+	CLOCKID_MAP("raw", CLOCK_MONOTONIC_RAW),
+	CLOCKID_MAP("real", CLOCK_REALTIME),
+	CLOCKID_MAP("boot", CLOCK_BOOTTIME),
+
+	CLOCKID_END,
+};
+
+static int parse_clockid(const struct option *opt, const char *str, int unset)
+{
+	struct record_opts *opts = (struct record_opts *)opt->value;
+	const struct clockid_map *cm;
+	const char *ostr = str;
+
+	if (unset) {
+		opts->use_clockid = 0;
+		return 0;
+	}
+
+	/* no arg passed */
+	if (!str)
+		return 0;
+
+	/* no setting it twice */
+	if (opts->use_clockid)
+		return -1;
+
+	opts->use_clockid = true;
+
+	/* if its a number, we're done */
+	if (sscanf(str, "%d", &opts->clockid) == 1)
+		return 0;
+
+	/* allow a "CLOCK_" prefix to the name */
+	if (!strncasecmp(str, "CLOCK_", 6))
+		str += 6;
+
+	for (cm = clockids; cm->name; cm++) {
+		if (!strcasecmp(str, cm->name)) {
+			opts->clockid = cm->clockid;
+			return 0;
+		}
+	}
+
+	opts->use_clockid = false;
+	ui__warning("unknown clockid %s, check man page\n", ostr);
+	return -1;
+}
+
 static const char * const __record_usage[] = {
 	"perf record [<options>] [<command>]",
 	"perf record [<options>] -- <command> [<options>]",
@@ -842,6 +926,9 @@ struct option __record_options[] = {
 		    "Sample machine registers on interrupt"),
 	OPT_BOOLEAN(0, "running-time", &record.opts.running_time,
 		    "Record running/enabled time of read (:S) events"),
+	OPT_CALLBACK('k', "clockid", &record.opts,
+	"clockid", "clockid to use for events, see clock_gettime()",
+	parse_clockid),
 	OPT_END()
 };