Re: [PATCH v1] perf record: encode -k clockid frequency into Perf trace

Alexey Budankov
2018-09-28T06:38:17Z

Hi,

On 27.09.2018 19:02, Jiri Olsa wrote:
> On Thu, Sep 27, 2018 at 03:54:03PM +0300, Alexey Budankov wrote:
>>
>> 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>
>
> looks good, few nits below

Accepted. Please see v2.

Thanks,
Alexey

>
> thanks,
> jirka
>
>
>> ---
>> tools/perf/builtin-record.c | 26 ++++++++++++++++++++++++--
>> tools/perf/perf.h | 1 +
>> tools/perf/util/env.h | 1 +
>> tools/perf/util/header.c | 32 ++++++++++++++++++++++++++++++++
>> tools/perf/util/header.h | 1 +
>> 5 files changed, 59 insertions(+), 2 deletions(-)
>>
>> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
>> index 0980dfe3396b..f215daf28508 100644
>> --- a/tools/perf/builtin-record.c
>> +++ b/tools/perf/builtin-record.c
>> @@ -592,6 +592,11 @@ 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_freq)
>> + session->header.env.clockid_freq = rec->opts.clockid_freq;
>> + else
>> + perf_header__clear_feat(&session->header, HEADER_CLOCKID);
>> +
>> perf_header__clear_feat(&session->header, HEADER_STAT);
>> }
>>
>> @@ -1337,6 +1342,22 @@ static const struct clockid_map clockids[] = {
>> CLOCKID_END,
>> };
>>
>> +#define NSEC_IN_SEC (1000 * 1000 * 1000)
>
> we have that one already:
>
> ../include/linux/time64.h:#define NSEC_PER_SEC 1000000000L
>
>> +
>> +static int get_clockid_freq(clockid_t clk_id, size_t *freq)
>> +{
>> + size_t period_ns;
>> + struct timespec res;
>> +
>> + *freq = 0;
>> + if (!clock_getres(clk_id, &res)) {
>> + period_ns = res.tv_nsec + res.tv_sec * NSEC_IN_SEC;
>> + *freq = period_ns * 1000; /* MHz */
>
> let's multiply it when we display it no?
> the field is called clockid_freq anyway...
>
>> + }
>> +
>> + 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 +1381,7 @@ 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_freq(opts->clockid, &opts->clockid_freq);
>>
>> /* allow a "CLOCK_" prefix to the name */
>> if (!strncasecmp(str, "CLOCK_", 6))
>> @@ -1369,7 +1390,8 @@ 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_freq(opts->clockid,
>> + &opts->clockid_freq);
>> }
>> }
>>
>> diff --git a/tools/perf/perf.h b/tools/perf/perf.h
>> index 21bf7f5a3cf5..7f612f296b64 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_freq;
>> unsigned int proc_map_timeout;
>> };
>>
>> diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h
>> index 1f3ccc368530..ffb358f1ff1e 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_freq;
>> };
>>
>> extern struct perf_env perf_env;
>> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
>> index 1ec1d9bc2d63..a37c40478b64 100644
>> --- a/tools/perf/util/header.c
>> +++ b/tools/perf/util/header.c
>> @@ -1034,6 +1034,19 @@ static int write_auxtrace(struct feat_fd *ff,
>> return err;
>> }
>>
>> +static int write_clockid(struct feat_fd *ff,
>> + struct perf_evlist *evlist __maybe_unused)
>> +{
>> + int ret;
>> +
>> + ret = do_write(ff, &ff->ph->env.clockid_freq,
>> + sizeof(ff->ph->env.clockid_freq));
>> + if (ret < 0)
>> + return ret;
>> +
>> + return 0;
>
> can't you just do: "return do_write(..." in here?
>
>> +}
>> +
>> 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 +1521,11 @@ 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: %ld MHz\n", ff->ph->env.clockid_freq);
>> +}
>> +
>> static void free_event_desc(struct perf_evsel *events)
>> {
>> struct perf_evsel *evsel;
>> @@ -2531,6 +2549,19 @@ static int process_mem_topology(struct feat_fd *ff,
>> return ret;
>> }
>>
>> +static int process_clockid(struct feat_fd *ff,
>> + void *data __maybe_unused)
>> +{
>> + size_t clockid_freq;
>> +
>> + if (do_read_u64(ff, &clockid_freq))
>> + return -1;
>> +
>> + ff->ph->env.clockid_freq = clockid_freq;
>> +
>> + 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 +2621,7 @@ 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,
>> };
>