[PATCH] perf, record: Add clockid parameter

[Peter Zijlstra <peterz@infradead.org>]

On Fri, Mar 27, 2015 at 04:48:08AM -0700, tip-bot for Peter Zijlstra wrote:
> perf: Add per event clockid support

And here the accompanying userspace; which I'd totally forgotten about.

XXX: do we want to store the clockid in the data file as well, such that
we can verify at perf-inject time the clocks match with our
expectations?

---
Subject: 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.

Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 tools/perf/builtin-record.c | 3 +++
 tools/perf/perf.h           | 1 +
 tools/perf/util/evsel.c     | 5 +++++
 3 files changed, 9 insertions(+)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 18aad239b401..9d4ed884b1c8 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -739,6 +739,7 @@ static struct record record = {
 			.uses_mmap   = true,
 			.default_per_cpu = true,
 		},
+		.clockid             = -1,
 	},
 	.tool = {
 		.sample		= process_sample_event,
@@ -842,6 +843,8 @@ 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_INTEGER('k', "clockid", &record.opts.clockid,
+		    "clockid to use for events"),
 	OPT_END()
 };
 
diff --git a/tools/perf/perf.h b/tools/perf/perf.h
index c38a085a5571..275c0c58fbbe 100644
--- a/tools/perf/perf.h
+++ b/tools/perf/perf.h
@@ -62,6 +62,7 @@ struct record_opts {
 	u64	     user_interval;
 	bool	     sample_transaction;
 	unsigned     initial_delay;
+	clockid_t    clockid;
 };
 
 struct option;
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 358e5954baa8..309208b16632 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -761,6 +761,11 @@ void perf_evsel__config(struct perf_evsel *evsel, struct record_opts *opts)
 		attr->disabled = 0;
 		attr->enable_on_exec = 0;
 	}
+
+	if (opts->clockid >= 0) {
+		attr->use_clockid = 1;
+		attr->clockid = opts->clockid;
+	}
 }
 
 static int perf_evsel__alloc_fd(struct perf_evsel *evsel, int ncpus, int nthreads)