[PATCH v4] perf record: encode -k clockid frequency into Perf trace
From: Alexey Budankov
Date: Tue Oct 09 2018 - 02:59:10 EST
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@xxxxxxxxxxxxxxx>
---
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 | 28 ++++++++++++++++++++++++++++
tools/perf/util/header.h | 1 +
5 files changed, 53 insertions(+), 2 deletions(-)
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 0980dfe3396b..d803d3264465 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, size_t *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..981db3c2ed60 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;
+ size_t clockid_res_ns;
unsigned int proc_map_timeout;
};
diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h
index 1f3ccc368530..b167a54d635f 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;
+ size_t 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..702e0cce63da 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -1034,6 +1034,14 @@ static int write_auxtrace(struct feat_fd *ff,
return err;
}
+static int write_clockid(struct feat_fd *ff,
+ struct perf_evlist *evlist __maybe_unused)
+{
+ u64 clockid_res_ns = ff->ph->env.clockid_res_ns;
+
+ return do_write(ff, &clockid_res_ns, sizeof(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 +1516,12 @@ 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: %zd MHz\n",
+ ff->ph->env.clockid_res_ns * 1000);
+}
+
static void free_event_desc(struct perf_evsel *events)
{
struct perf_evsel *evsel;
@@ -2531,6 +2545,19 @@ static int process_mem_topology(struct feat_fd *ff,
return ret;
}
+static int process_clockid(struct feat_fd *ff,
+ void *data __maybe_unused)
+{
+ u64 clockid_res_ns;
+
+ if (do_read_u64(ff, &clockid_res_ns))
+ return -1;
+
+ ff->ph->env.clockid_res_ns = *(size_t *)&clockid_res_ns;
+
+ 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 +2617,7 @@ 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,
};