Add support for new clock IDs CLOCK_PERF_HW_CLOCK and
CLOCK_PERF_HW_CLOCK_NS.
Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
---
tools/include/uapi/linux/perf_event.h | 14 ++++++++++++++
tools/perf/Documentation/perf-record.txt | 9 ++++++++-
tools/perf/builtin-record.c | 2 +-
tools/perf/util/clockid.c | 5 +++++
4 files changed, 28 insertions(+), 2 deletions(-)
diff --git a/tools/include/uapi/linux/perf_event.h b/tools/include/uapi/linux/perf_event.h
index 1b65042ab1db..9fbb2eddd2ca 100644
--- a/tools/include/uapi/linux/perf_event.h
+++ b/tools/include/uapi/linux/perf_event.h
@@ -290,6 +290,20 @@ enum {
PERF_TXN_ABORT_SHIFT = 32,
};
+/*
+ * If supported, clockid value to select an architecture dependent hardware
+ * clock. Note this means the unit of time is ticks not nanoseconds.
+ * On x86, this is provided by the rdtsc instruction, and is not
+ * paravirtualized.
+ */
+#define CLOCK_PERF_HW_CLOCK 0x10000000
+/*
+ * Same as CLOCK_PERF_HW_CLOCK but in nanoseconds. Note support of
+ * CLOCK_PERF_HW_CLOCK_NS does not necesssarily imply support of
+ * CLOCK_PERF_HW_CLOCK or vice versa.
+ */
+#define CLOCK_PERF_HW_CLOCK_NS 0x10000001
+
/*
* The format of the data returned by read() on a perf event fd,
* as specified by attr.read_format:
diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
index 9ccc75935bc5..a5ef4813093a 100644
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -444,7 +444,14 @@ Record running and enabled time for read events (:S)
Sets the clock id to use for the various time fields in the perf_event_type
records. See clock_gettime(). In particular CLOCK_MONOTONIC and
CLOCK_MONOTONIC_RAW are supported, some events might also allow
-CLOCK_BOOTTIME, CLOCK_REALTIME and CLOCK_TAI.
+CLOCK_BOOTTIME, CLOCK_REALTIME and CLOCK_TAI. In addition, the kernel might
+support CLOCK_PERF_HW_CLOCK to select an architecture dependent hardware
+clock, for which the unit of time is ticks not nanoseconds. On x86,
+CLOCK_PERF_HW_CLOCK is provided by the rdtsc instruction, and is not
+paravirtualized. There is also CLOCK_PERF_HW_CLOCK_NS which is the same as
+CLOCK_PERF_HW_CLOCK, but converted to nanoseconds. Note support of
+CLOCK_PERF_HW_CLOCK_NS does not necessarily imply support of
+CLOCK_PERF_HW_CLOCK or vice versa.
-S::
--snapshot::
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index bb716c953d02..52eaffa0b77f 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -1553,7 +1553,7 @@ static int record__init_clock(struct record *rec)
struct timeval ref_tod;
u64 ref;
- if (!rec->opts.use_clockid)
+ if (!rec->opts.use_clockid || rec->opts.clockid >= CLOCK_PERF_HW_CLOCK)
return 0;
if (rec->opts.use_clockid && rec->opts.clockid_res_ns)
diff --git a/tools/perf/util/clockid.c b/tools/perf/util/clockid.c
index 74365a5d99c1..380429725df1 100644
--- a/tools/perf/util/clockid.c
+++ b/tools/perf/util/clockid.c
@@ -49,6 +49,9 @@ static const struct clockid_map clockids[] = {
CLOCKID_MAP("real", CLOCK_REALTIME),
CLOCKID_MAP("boot", CLOCK_BOOTTIME),
+ CLOCKID_MAP("perf_hw_clock", CLOCK_PERF_HW_CLOCK),
+ CLOCKID_MAP("perf_hw_clock_ns", CLOCK_PERF_HW_CLOCK_NS),
+
CLOCKID_END,
};
@@ -57,6 +60,8 @@ static int get_clockid_res(clockid_t clk_id, u64 *res_ns)
struct timespec res;
*res_ns = 0;
+ if (clk_id >= CLOCK_PERF_HW_CLOCK)
+ return 0;
if (!clock_getres(clk_id, &res))
*res_ns = res.tv_nsec + res.tv_sec * NSEC_PER_SEC;
else
--
2.25.1
