[PATCH v5] perf record: encode -k clockid frequency into Perf trace

[PATCH v5] perf record: encode -k clockid frequency into Perf trace

[Alexey Budankov]

Store -k clockid frequency into Perf trace to enable timestamps 
derived metrics conversion into wall clock time on reporting stage.

Below is the example of perf report output:

  tools/perf/perf record -k raw -- ../../matrix/linux/matrix.gcc
  ...
  [ perf record: Captured and wrote 31.222 MB perf.data (818054 samples) ]
  
  tools/perf/perf report --header
  # ========
  ...
  # event : name = cycles:ppp, , size = 112, { sample_period, sample_freq } = 4000, sample_type = IP|TID|TIME|PERIOD, disabled = 1, inherit = 1, mmap = 1, comm = 1, freq = 1, enable_on_exec = 1, task = 1, precise_ip = 3, sample_id_all = 1, exclude_guest = 1, mmap2 = 1, comm_exec = 1, use_clockid = 1, clockid = 4
  ...
  # clockid frequency: 1000 MHz
  ...
  # ========

Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
---
Changes in v5:
 - use u64 for clockid_res_ns values to simplify operations with trace header
Changes in v4:
 - addressed compilation issues on 32bit platforms
Changes in v3:
 - moved header's clockid_res_ns initialization out of record__init_features()
 - added explicit warning for case of failed clock_getres() call
Changes in v2:
 - renamed clockid_freq to clockid_res_ns and get_clockid_freq() to get_clockid_res()
 - avoided redundant define of NSEC_IN_SEC, reused linux/time64.h:NSEC_PER_SEC
 - moved MHz conversion into print_clockid() and shortened write_clockid()
---
 tools/perf/builtin-record.c | 24 ++++++++++++++++++++++--
 tools/perf/perf.h           |  1 +
 tools/perf/util/env.h       |  1 +
 tools/perf/util/header.c    | 23 +++++++++++++++++++++++
 tools/perf/util/header.h    |  1 +
 5 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 0980dfe3396b..10cf889c6d75 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -592,6 +592,9 @@ static void record__init_features(struct record *rec)
 	if (!rec->opts.full_auxtrace)
 		perf_header__clear_feat(&session->header, HEADER_AUXTRACE);
 
+	if (!(rec->opts.use_clockid && rec->opts.clockid_res_ns))
+		perf_header__clear_feat(&session->header, HEADER_CLOCKID);
+
 	perf_header__clear_feat(&session->header, HEADER_STAT);
 }
 
@@ -897,6 +900,9 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
 
 	record__init_features(rec);
 
+	if (rec->opts.use_clockid && rec->opts.clockid_res_ns)
+		session->header.env.clockid_res_ns = rec->opts.clockid_res_ns;
+
 	if (forks) {
 		err = perf_evlist__prepare_workload(rec->evlist, &opts->target,
 						    argv, data->is_pipe,
@@ -1337,6 +1343,19 @@ static const struct clockid_map clockids[] = {
 	CLOCKID_END,
 };
 
+static int get_clockid_res(clockid_t clk_id, u64 *res_ns)
+{
+	struct timespec res;
+
+	*res_ns = 0;
+	if (!clock_getres(clk_id, &res))
+		*res_ns = res.tv_nsec + res.tv_sec * NSEC_PER_SEC;
+	else
+		pr_warning("WARNING: Failed to determine specified clock resolution.\n");
+
+	return 0;
+}
+
 static int parse_clockid(const struct option *opt, const char *str, int unset)
 {
 	struct record_opts *opts = (struct record_opts *)opt->value;
@@ -1360,7 +1379,7 @@ static int parse_clockid(const struct option *opt, const char *str, int unset)
 
 	/* if its a number, we're done */
 	if (sscanf(str, "%d", &opts->clockid) == 1)
-		return 0;
+		return get_clockid_res(opts->clockid, &opts->clockid_res_ns);
 
 	/* allow a "CLOCK_" prefix to the name */
 	if (!strncasecmp(str, "CLOCK_", 6))
@@ -1369,7 +1388,8 @@ static int parse_clockid(const struct option *opt, const char *str, int unset)
 	for (cm = clockids; cm->name; cm++) {
 		if (!strcasecmp(str, cm->name)) {
 			opts->clockid = cm->clockid;
-			return 0;
+			return get_clockid_res(opts->clockid,
+					       &opts->clockid_res_ns);
 		}
 	}
 
diff --git a/tools/perf/perf.h b/tools/perf/perf.h
index 21bf7f5a3cf5..0ed4a34c74c4 100644
--- a/tools/perf/perf.h
+++ b/tools/perf/perf.h
@@ -81,6 +81,7 @@ struct record_opts {
 	unsigned     initial_delay;
 	bool         use_clockid;
 	clockid_t    clockid;
+	u64          clockid_res_ns;
 	unsigned int proc_map_timeout;
 };
 
diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h
index 1f3ccc368530..d01b8355f4ca 100644
--- a/tools/perf/util/env.h
+++ b/tools/perf/util/env.h
@@ -63,6 +63,7 @@ struct perf_env {
 	struct numa_node	*numa_nodes;
 	struct memory_node	*memory_nodes;
 	unsigned long long	 memory_bsize;
+	u64                     clockid_res_ns;
 };
 
 extern struct perf_env perf_env;
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 1ec1d9bc2d63..4fd45be95a43 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -1034,6 +1034,13 @@ static int write_auxtrace(struct feat_fd *ff,
 	return err;
 }
 
+static int write_clockid(struct feat_fd *ff,
+			 struct perf_evlist *evlist __maybe_unused)
+{
+	return do_write(ff, &ff->ph->env.clockid_res_ns,
+			sizeof(ff->ph->env.clockid_res_ns));
+}
+
 static int cpu_cache_level__sort(const void *a, const void *b)
 {
 	struct cpu_cache_level *cache_a = (struct cpu_cache_level *)a;
@@ -1508,6 +1515,12 @@ static void print_cpu_topology(struct feat_fd *ff, FILE *fp)
 		fprintf(fp, "# Core ID and Socket ID information is not available\n");
 }
 
+static void print_clockid(struct feat_fd *ff, FILE *fp)
+{
+	fprintf(fp, "# clockid frequency: %"PRIu64" MHz\n",
+		ff->ph->env.clockid_res_ns * 1000);
+}
+
 static void free_event_desc(struct perf_evsel *events)
 {
 	struct perf_evsel *evsel;
@@ -2531,6 +2544,15 @@ static int process_mem_topology(struct feat_fd *ff,
 	return ret;
 }
 
+static int process_clockid(struct feat_fd *ff,
+			   void *data __maybe_unused)
+{
+	if (do_read_u64(ff, &ff->ph->env.clockid_res_ns))
+		return -1;
+
+	return 0;
+}
+
 struct feature_ops {
 	int (*write)(struct feat_fd *ff, struct perf_evlist *evlist);
 	void (*print)(struct feat_fd *ff, FILE *fp);
@@ -2590,6 +2612,7 @@ static const struct feature_ops feat_ops[HEADER_LAST_FEATURE] = {
 	FEAT_OPN(CACHE,		cache,		true),
 	FEAT_OPR(SAMPLE_TIME,	sample_time,	false),
 	FEAT_OPR(MEM_TOPOLOGY,	mem_topology,	true),
+	FEAT_OPR(CLOCKID,       clockid,        false)
 };
 
 struct header_print_data {
diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h
index e17903caa71d..0d553ddca0a3 100644
--- a/tools/perf/util/header.h
+++ b/tools/perf/util/header.h
@@ -38,6 +38,7 @@ enum {
 	HEADER_CACHE,
 	HEADER_SAMPLE_TIME,
 	HEADER_MEM_TOPOLOGY,
+	HEADER_CLOCKID,
 	HEADER_LAST_FEATURE,
 	HEADER_FEAT_BITS	= 256,
 };

Re: [PATCH v5] perf record: encode -k clockid frequency into Perf trace

[Arnaldo Carvalho de Melo]

Em Tue, Oct 09, 2018 at 05:36:24PM +0300, Alexey Budankov escreveu:
> 
> Store -k clockid frequency into Perf trace to enable timestamps 
> derived metrics conversion into wall clock time on reporting stage.
> 
> Below is the example of perf report output:

Applied, building, lets see this time.

- Arnaldo
 
>   tools/perf/perf record -k raw -- ../../matrix/linux/matrix.gcc
>   ...
>   [ perf record: Captured and wrote 31.222 MB perf.data (818054 samples) ]
>   
>   tools/perf/perf report --header
>   # ========
>   ...
>   # event : name = cycles:ppp, , size = 112, { sample_period, sample_freq } = 4000, sample_type = IP|TID|TIME|PERIOD, disabled = 1, inherit = 1, mmap = 1, comm = 1, freq = 1, enable_on_exec = 1, task = 1, precise_ip = 3, sample_id_all = 1, exclude_guest = 1, mmap2 = 1, comm_exec = 1, use_clockid = 1, clockid = 4
>   ...
>   # clockid frequency: 1000 MHz
>   ...
>   # ========
> 
> Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
> ---
> Changes in v5:
>  - use u64 for clockid_res_ns values to simplify operations with trace header
> Changes in v4:
>  - addressed compilation issues on 32bit platforms
> Changes in v3:
>  - moved header's clockid_res_ns initialization out of record__init_features()
>  - added explicit warning for case of failed clock_getres() call
> Changes in v2:
>  - renamed clockid_freq to clockid_res_ns and get_clockid_freq() to get_clockid_res()
>  - avoided redundant define of NSEC_IN_SEC, reused linux/time64.h:NSEC_PER_SEC
>  - moved MHz conversion into print_clockid() and shortened write_clockid()
> ---
>  tools/perf/builtin-record.c | 24 ++++++++++++++++++++++--
>  tools/perf/perf.h           |  1 +
>  tools/perf/util/env.h       |  1 +
>  tools/perf/util/header.c    | 23 +++++++++++++++++++++++
>  tools/perf/util/header.h    |  1 +
>  5 files changed, 48 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index 0980dfe3396b..10cf889c6d75 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -592,6 +592,9 @@ static void record__init_features(struct record *rec)
>  	if (!rec->opts.full_auxtrace)
>  		perf_header__clear_feat(&session->header, HEADER_AUXTRACE);
>  
> +	if (!(rec->opts.use_clockid && rec->opts.clockid_res_ns))
> +		perf_header__clear_feat(&session->header, HEADER_CLOCKID);
> +
>  	perf_header__clear_feat(&session->header, HEADER_STAT);
>  }
>  
> @@ -897,6 +900,9 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
>  
>  	record__init_features(rec);
>  
> +	if (rec->opts.use_clockid && rec->opts.clockid_res_ns)
> +		session->header.env.clockid_res_ns = rec->opts.clockid_res_ns;
> +
>  	if (forks) {
>  		err = perf_evlist__prepare_workload(rec->evlist, &opts->target,
>  						    argv, data->is_pipe,
> @@ -1337,6 +1343,19 @@ static const struct clockid_map clockids[] = {
>  	CLOCKID_END,
>  };
>  
> +static int get_clockid_res(clockid_t clk_id, u64 *res_ns)
> +{
> +	struct timespec res;
> +
> +	*res_ns = 0;
> +	if (!clock_getres(clk_id, &res))
> +		*res_ns = res.tv_nsec + res.tv_sec * NSEC_PER_SEC;
> +	else
> +		pr_warning("WARNING: Failed to determine specified clock resolution.\n");
> +
> +	return 0;
> +}
> +
>  static int parse_clockid(const struct option *opt, const char *str, int unset)
>  {
>  	struct record_opts *opts = (struct record_opts *)opt->value;
> @@ -1360,7 +1379,7 @@ static int parse_clockid(const struct option *opt, const char *str, int unset)
>  
>  	/* if its a number, we're done */
>  	if (sscanf(str, "%d", &opts->clockid) == 1)
> -		return 0;
> +		return get_clockid_res(opts->clockid, &opts->clockid_res_ns);
>  
>  	/* allow a "CLOCK_" prefix to the name */
>  	if (!strncasecmp(str, "CLOCK_", 6))
> @@ -1369,7 +1388,8 @@ static int parse_clockid(const struct option *opt, const char *str, int unset)
>  	for (cm = clockids; cm->name; cm++) {
>  		if (!strcasecmp(str, cm->name)) {
>  			opts->clockid = cm->clockid;
> -			return 0;
> +			return get_clockid_res(opts->clockid,
> +					       &opts->clockid_res_ns);
>  		}
>  	}
>  
> diff --git a/tools/perf/perf.h b/tools/perf/perf.h
> index 21bf7f5a3cf5..0ed4a34c74c4 100644
> --- a/tools/perf/perf.h
> +++ b/tools/perf/perf.h
> @@ -81,6 +81,7 @@ struct record_opts {
>  	unsigned     initial_delay;
>  	bool         use_clockid;
>  	clockid_t    clockid;
> +	u64          clockid_res_ns;
>  	unsigned int proc_map_timeout;
>  };
>  
> diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h
> index 1f3ccc368530..d01b8355f4ca 100644
> --- a/tools/perf/util/env.h
> +++ b/tools/perf/util/env.h
> @@ -63,6 +63,7 @@ struct perf_env {
>  	struct numa_node	*numa_nodes;
>  	struct memory_node	*memory_nodes;
>  	unsigned long long	 memory_bsize;
> +	u64                     clockid_res_ns;
>  };
>  
>  extern struct perf_env perf_env;
> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
> index 1ec1d9bc2d63..4fd45be95a43 100644
> --- a/tools/perf/util/header.c
> +++ b/tools/perf/util/header.c
> @@ -1034,6 +1034,13 @@ static int write_auxtrace(struct feat_fd *ff,
>  	return err;
>  }
>  
> +static int write_clockid(struct feat_fd *ff,
> +			 struct perf_evlist *evlist __maybe_unused)
> +{
> +	return do_write(ff, &ff->ph->env.clockid_res_ns,
> +			sizeof(ff->ph->env.clockid_res_ns));
> +}
> +
>  static int cpu_cache_level__sort(const void *a, const void *b)
>  {
>  	struct cpu_cache_level *cache_a = (struct cpu_cache_level *)a;
> @@ -1508,6 +1515,12 @@ static void print_cpu_topology(struct feat_fd *ff, FILE *fp)
>  		fprintf(fp, "# Core ID and Socket ID information is not available\n");
>  }
>  
> +static void print_clockid(struct feat_fd *ff, FILE *fp)
> +{
> +	fprintf(fp, "# clockid frequency: %"PRIu64" MHz\n",
> +		ff->ph->env.clockid_res_ns * 1000);
> +}
> +
>  static void free_event_desc(struct perf_evsel *events)
>  {
>  	struct perf_evsel *evsel;
> @@ -2531,6 +2544,15 @@ static int process_mem_topology(struct feat_fd *ff,
>  	return ret;
>  }
>  
> +static int process_clockid(struct feat_fd *ff,
> +			   void *data __maybe_unused)
> +{
> +	if (do_read_u64(ff, &ff->ph->env.clockid_res_ns))
> +		return -1;
> +
> +	return 0;
> +}
> +
>  struct feature_ops {
>  	int (*write)(struct feat_fd *ff, struct perf_evlist *evlist);
>  	void (*print)(struct feat_fd *ff, FILE *fp);
> @@ -2590,6 +2612,7 @@ static const struct feature_ops feat_ops[HEADER_LAST_FEATURE] = {
>  	FEAT_OPN(CACHE,		cache,		true),
>  	FEAT_OPR(SAMPLE_TIME,	sample_time,	false),
>  	FEAT_OPR(MEM_TOPOLOGY,	mem_topology,	true),
> +	FEAT_OPR(CLOCKID,       clockid,        false)
>  };
>  
>  struct header_print_data {
> diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h
> index e17903caa71d..0d553ddca0a3 100644
> --- a/tools/perf/util/header.h
> +++ b/tools/perf/util/header.h
> @@ -38,6 +38,7 @@ enum {
>  	HEADER_CACHE,
>  	HEADER_SAMPLE_TIME,
>  	HEADER_MEM_TOPOLOGY,
> +	HEADER_CLOCKID,
>  	HEADER_LAST_FEATURE,
>  	HEADER_FEAT_BITS	= 256,
>  };

Re: [PATCH v5] perf record: encode -k clockid frequency into Perf trace

[Alexey Budankov]

Hi Arnaldo,

On 09.10.2018 22:32, Arnaldo Carvalho de Melo wrote:
> Em Tue, Oct 09, 2018 at 05:36:24PM +0300, Alexey Budankov escreveu:
>>
>> Store -k clockid frequency into Perf trace to enable timestamps 
>> derived metrics conversion into wall clock time on reporting stage.
>>
>> Below is the example of perf report output:
> 
> Applied, building, lets see this time.

Thanks for the effort. So far I assume the outstanding issues 
were addressed. Is the patch still planned for coming release?

Thanks,
Alexey

Re: [PATCH v5] perf record: encode -k clockid frequency into Perf trace

[Arnaldo Carvalho de Melo]

Em Tue, Oct 23, 2018 at 02:43:05PM +0300, Alexey Budankov escreveu:
> Hi Arnaldo,
> 
> On 09.10.2018 22:32, Arnaldo Carvalho de Melo wrote:
> > Em Tue, Oct 09, 2018 at 05:36:24PM +0300, Alexey Budankov escreveu:
> >>
> >> Store -k clockid frequency into Perf trace to enable timestamps 
> >> derived metrics conversion into wall clock time on reporting stage.
> >>
> >> Below is the example of perf report output:
> > 
> > Applied, building, lets see this time.
> 
> Thanks for the effort. So far I assume the outstanding issues 
> were addressed. Is the patch still planned for coming release?

yep, its in my perf/core branch:

https://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git/commit/?h=perf/core&id=cf7905165fee15fe26ac4a91ee0a35b966249430

I'll process some more patches from Adrian and Andi today, both making
use of Intel Xed, that seems to be installed ok now in my test machines,
and then send a pull req to Ingo,

Thanks,

- Arnaldo

[tip:perf/urgent] perf record: Encode -k clockid frequency into Perf trace

[tip-bot for Alexey Budankov]

Commit-ID:  cf7905165fee15fe26ac4a91ee0a35b966249430
Gitweb:     https://git.kernel.org/tip/cf7905165fee15fe26ac4a91ee0a35b966249430
Author:     Alexey Budankov <alexey.budankov@linux.intel.com>
AuthorDate: Tue, 9 Oct 2018 17:36:24 +0300
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Thu, 18 Oct 2018 11:16:38 -0300

perf record: Encode -k clockid frequency into Perf trace

Store -k clockid frequency into Perf trace to enable timestamps
derived metrics conversion into wall clock time on reporting stage.

Below is the example of perf report output:

  tools/perf/perf record -k raw -- ../../matrix/linux/matrix.gcc
  ...
  [ perf record: Captured and wrote 31.222 MB perf.data (818054 samples) ]

  tools/perf/perf report --header
  # ========
  ...
  # event : name = cycles:ppp, , size = 112, { sample_period, sample_freq } = 4000, sample_type = IP|TID|TIME|PERIOD, disabled = 1, inherit = 1, mmap = 1, comm = 1, freq = 1, enable_on_exec = 1, task = 1, precise_ip = 3, sample_id_all = 1, exclude_guest = 1, mmap2 = 1, comm_exec = 1, use_clockid = 1, clockid = 4
  ...
  # clockid frequency: 1000 MHz
  ...
  # ========

Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/23a4a1dc-b160-85a0-347d-40a2ed6d007b@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/builtin-record.c | 24 ++++++++++++++++++++++--
 tools/perf/perf.h           |  1 +
 tools/perf/util/env.h       |  1 +
 tools/perf/util/header.c    | 23 +++++++++++++++++++++++
 tools/perf/util/header.h    |  1 +
 5 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 0980dfe3396b..10cf889c6d75 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -592,6 +592,9 @@ static void record__init_features(struct record *rec)
 	if (!rec->opts.full_auxtrace)
 		perf_header__clear_feat(&session->header, HEADER_AUXTRACE);
 
+	if (!(rec->opts.use_clockid && rec->opts.clockid_res_ns))
+		perf_header__clear_feat(&session->header, HEADER_CLOCKID);
+
 	perf_header__clear_feat(&session->header, HEADER_STAT);
 }
 
@@ -897,6 +900,9 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
 
 	record__init_features(rec);
 
+	if (rec->opts.use_clockid && rec->opts.clockid_res_ns)
+		session->header.env.clockid_res_ns = rec->opts.clockid_res_ns;
+
 	if (forks) {
 		err = perf_evlist__prepare_workload(rec->evlist, &opts->target,
 						    argv, data->is_pipe,
@@ -1337,6 +1343,19 @@ static const struct clockid_map clockids[] = {
 	CLOCKID_END,
 };
 
+static int get_clockid_res(clockid_t clk_id, u64 *res_ns)
+{
+	struct timespec res;
+
+	*res_ns = 0;
+	if (!clock_getres(clk_id, &res))
+		*res_ns = res.tv_nsec + res.tv_sec * NSEC_PER_SEC;
+	else
+		pr_warning("WARNING: Failed to determine specified clock resolution.\n");
+
+	return 0;
+}
+
 static int parse_clockid(const struct option *opt, const char *str, int unset)
 {
 	struct record_opts *opts = (struct record_opts *)opt->value;
@@ -1360,7 +1379,7 @@ static int parse_clockid(const struct option *opt, const char *str, int unset)
 
 	/* if its a number, we're done */
 	if (sscanf(str, "%d", &opts->clockid) == 1)
-		return 0;
+		return get_clockid_res(opts->clockid, &opts->clockid_res_ns);
 
 	/* allow a "CLOCK_" prefix to the name */
 	if (!strncasecmp(str, "CLOCK_", 6))
@@ -1369,7 +1388,8 @@ static int parse_clockid(const struct option *opt, const char *str, int unset)
 	for (cm = clockids; cm->name; cm++) {
 		if (!strcasecmp(str, cm->name)) {
 			opts->clockid = cm->clockid;
-			return 0;
+			return get_clockid_res(opts->clockid,
+					       &opts->clockid_res_ns);
 		}
 	}
 
diff --git a/tools/perf/perf.h b/tools/perf/perf.h
index 21bf7f5a3cf5..0ed4a34c74c4 100644
--- a/tools/perf/perf.h
+++ b/tools/perf/perf.h
@@ -81,6 +81,7 @@ struct record_opts {
 	unsigned     initial_delay;
 	bool         use_clockid;
 	clockid_t    clockid;
+	u64          clockid_res_ns;
 	unsigned int proc_map_timeout;
 };
 
diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h
index 1f3ccc368530..d01b8355f4ca 100644
--- a/tools/perf/util/env.h
+++ b/tools/perf/util/env.h
@@ -63,6 +63,7 @@ struct perf_env {
 	struct numa_node	*numa_nodes;
 	struct memory_node	*memory_nodes;
 	unsigned long long	 memory_bsize;
+	u64                     clockid_res_ns;
 };
 
 extern struct perf_env perf_env;
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 1ec1d9bc2d63..4fd45be95a43 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -1034,6 +1034,13 @@ static int write_auxtrace(struct feat_fd *ff,
 	return err;
 }
 
+static int write_clockid(struct feat_fd *ff,
+			 struct perf_evlist *evlist __maybe_unused)
+{
+	return do_write(ff, &ff->ph->env.clockid_res_ns,
+			sizeof(ff->ph->env.clockid_res_ns));
+}
+
 static int cpu_cache_level__sort(const void *a, const void *b)
 {
 	struct cpu_cache_level *cache_a = (struct cpu_cache_level *)a;
@@ -1508,6 +1515,12 @@ static void print_cpu_topology(struct feat_fd *ff, FILE *fp)
 		fprintf(fp, "# Core ID and Socket ID information is not available\n");
 }
 
+static void print_clockid(struct feat_fd *ff, FILE *fp)
+{
+	fprintf(fp, "# clockid frequency: %"PRIu64" MHz\n",
+		ff->ph->env.clockid_res_ns * 1000);
+}
+
 static void free_event_desc(struct perf_evsel *events)
 {
 	struct perf_evsel *evsel;
@@ -2531,6 +2544,15 @@ out:
 	return ret;
 }
 
+static int process_clockid(struct feat_fd *ff,
+			   void *data __maybe_unused)
+{
+	if (do_read_u64(ff, &ff->ph->env.clockid_res_ns))
+		return -1;
+
+	return 0;
+}
+
 struct feature_ops {
 	int (*write)(struct feat_fd *ff, struct perf_evlist *evlist);
 	void (*print)(struct feat_fd *ff, FILE *fp);
@@ -2590,6 +2612,7 @@ static const struct feature_ops feat_ops[HEADER_LAST_FEATURE] = {
 	FEAT_OPN(CACHE,		cache,		true),
 	FEAT_OPR(SAMPLE_TIME,	sample_time,	false),
 	FEAT_OPR(MEM_TOPOLOGY,	mem_topology,	true),
+	FEAT_OPR(CLOCKID,       clockid,        false)
 };
 
 struct header_print_data {
diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h
index e17903caa71d..0d553ddca0a3 100644
--- a/tools/perf/util/header.h
+++ b/tools/perf/util/header.h
@@ -38,6 +38,7 @@ enum {
 	HEADER_CACHE,
 	HEADER_SAMPLE_TIME,
 	HEADER_MEM_TOPOLOGY,
+	HEADER_CLOCKID,
 	HEADER_LAST_FEATURE,
 	HEADER_FEAT_BITS	= 256,
 };