* [PATCH v4] perf record: encode -k clockid frequency into Perf trace
@ 2018-10-09 6:59 Alexey Budankov
2018-10-09 13:41 ` Arnaldo Carvalho de Melo
0 siblings, 1 reply; 3+ messages in thread
From: Alexey Budankov @ 2018-10-09 6:59 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo
Cc: Alexander Shishkin, Jiri Olsa, Namhyung Kim, Andi Kleen, linux-kernel
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 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 +
| 28 ++++++++++++++++++++++++++++
| 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;
--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 {
--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,
};
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v4] perf record: encode -k clockid frequency into Perf trace
2018-10-09 6:59 [PATCH v4] perf record: encode -k clockid frequency into Perf trace Alexey Budankov
@ 2018-10-09 13:41 ` Arnaldo Carvalho de Melo
2018-10-09 14:36 ` Alexey Budankov
0 siblings, 1 reply; 3+ messages in thread
From: Arnaldo Carvalho de Melo @ 2018-10-09 13:41 UTC (permalink / raw)
To: Alexey Budankov
Cc: Peter Zijlstra, Ingo Molnar, Alexander Shishkin, Jiri Olsa,
Namhyung Kim, Andi Kleen, linux-kernel
Em Tue, Oct 09, 2018 at 09:59:03AM +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:
Some questions below, left the code for easier reference.
> 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 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;
What is wrong with:
ff->ph->env.clockid_res_ns = clockid_res_ns;
?
Also why have you picked 'size_t' for that nanoseconds variable
(clockid_res_ns)?
When one looks at things like:
struct timespec {
time_t tv_sec; /* seconds */
long tv_nsec; /* nanoseconds */
};
that would lead one to use 'long' for a variable holding nanoseconds,
no?
And 'timespec' is what clock_getres() uses:
int clock_getres(clockid_t clk_id, struct timespec *res);
Since you're storing this as:
+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;
Why don't you make ff->ph->env.clockid_res_ns an 'u64'? Would simplify
the code a bit, no?
Am I missing something?
- Arnaldo
> + 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,
> };
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v4] perf record: encode -k clockid frequency into Perf trace
2018-10-09 13:41 ` Arnaldo Carvalho de Melo
@ 2018-10-09 14:36 ` Alexey Budankov
0 siblings, 0 replies; 3+ messages in thread
From: Alexey Budankov @ 2018-10-09 14:36 UTC (permalink / raw)
To: Arnaldo Carvalho de Melo
Cc: Peter Zijlstra, Ingo Molnar, Alexander Shishkin, Jiri Olsa,
Namhyung Kim, Andi Kleen, linux-kernel
Hi,
On 09.10.2018 16:41, Arnaldo Carvalho de Melo wrote:
> Em Tue, Oct 09, 2018 at 09:59:03AM +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:
>
> Some questions below, left the code for easier reference.
>
>> 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 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;
>
> What is wrong with:
>
> ff->ph->env.clockid_res_ns = clockid_res_ns;
>
> ?
It can lead to implicit type size reduction, so compiler can
report warning what breaks compilation.
>
> Also why have you picked 'size_t' for that nanoseconds variable
> (clockid_res_ns)?
>
> When one looks at things like:
>
> struct timespec {
> time_t tv_sec; /* seconds */
> long tv_nsec; /* nanoseconds */
> };
>
> that would lead one to use 'long' for a variable holding nanoseconds,
> no?
Yes, long type for clockid_res_ns is what it was before
I had started to prepare the patch :)
>
> And 'timespec' is what clock_getres() uses:
>
> int clock_getres(clockid_t clk_id, struct timespec *res);
>
> Since you're storing this as:
>
> +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;
but then I thought a little bit more and came to conclusion that
for this multiplication with addition would probably better
have larger type than long.
>
> Why don't you make ff->ph->env.clockid_res_ns an 'u64'? Would simplify
> the code a bit, no?
and now I think that keeping things simple is the best approach. :)
>
> Am I missing something?
Please see v5. Thanks!
Have a good day,
Alexey
>
> - Arnaldo
>
>> + 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,
>> };
>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2018-10-09 14:36 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-10-09 6:59 [PATCH v4] perf record: encode -k clockid frequency into Perf trace Alexey Budankov
2018-10-09 13:41 ` Arnaldo Carvalho de Melo
2018-10-09 14:36 ` Alexey Budankov
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).