lkml.org 
[lkml]   [2020]   [Aug]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 2/6] perf tools: Store clock references for -k/--clockid option
On Thu, Jul 30, 2020 at 11:39:46PM +0200, Jiri Olsa wrote:
> Adding new CLOCK_DATA feature that stores reference times
> when -k/--clockid option is specified.
>
> It contains clock id and its reference time together with
> wall clock time taken at the 'same time', both values are
> in nanoseconds.
>
> The format of data is as below:
>
> struct {
> u32 version; /* version = 1 */
> u32 clockid;
> u64 clockid_time_ns;
> u64 wall_clock_ns;
> };
>
> This clock reference times will be used in following changes
> to display wall clock for perf events.
>
> It's available only for recording with clockid specified,
> because it's the only case where we can get reference time
> to wallclock time. It's can't do that with perf clock yet.
>
> Original-patch-by: David Ahern <dsahern@gmail.com>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
> .../Documentation/perf.data-file-format.txt | 13 ++
> tools/perf/builtin-record.c | 41 +++++++
> tools/perf/util/env.h | 12 ++
> tools/perf/util/header.c | 112 ++++++++++++++++++
> tools/perf/util/header.h | 1 +
> 5 files changed, 179 insertions(+)
>
> diff --git a/tools/perf/Documentation/perf.data-file-format.txt b/tools/perf/Documentation/perf.data-file-format.txt
> index b6472e463284..c484e81987c7 100644
> --- a/tools/perf/Documentation/perf.data-file-format.txt
> +++ b/tools/perf/Documentation/perf.data-file-format.txt
> @@ -389,6 +389,19 @@ struct {
> Example:
> cpu pmu capabilities: branches=32, max_precise=3, pmu_name=icelake
>
> + HEADER_CLOCK_DATA = 29,
> +
> + Contains clock id and its reference time together with wall clock
> + time taken at the 'same time', both values are in nanoseconds.
> + The format of data is as below.
> +
> +struct {
> + u32 version; /* version = 1 */
> + u32 clockid;
> + u64 clockid_time_ns;
> + u64 wall_clock_ns;
> +};
> +

It seems that it's slightly different than what it actually write to a file.
Specifically the last two fields should be reversed IMHO.


> other bits are reserved and should ignored for now
> HEADER_FEAT_BITS = 256,
>
[SNIP]

> diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h
> index 1ab2682d5d2b..4098a63d5e64 100644
> --- a/tools/perf/util/env.h
> +++ b/tools/perf/util/env.h
> @@ -100,6 +100,18 @@ struct perf_env {
> /* For fast cpu to numa node lookup via perf_env__numa_node */
> int *numa_map;
> int nr_numa_map;
> +
> + /* For real clock time refference. */

typo: reference

> + struct {
> + u64 tod_ns;
> + u64 clockid_ns;
> + int clockid;
> + /*
> + * enabled is valid for report mode, and is true if above
> + * values are set, it's set in process_clock_data
> + */
> + bool enabled;
> + } clock;
> };
>
> enum perf_compress_type {

[SNIP]
> +static void print_clock_data(struct feat_fd *ff, FILE *fp)
> +{
> + struct timespec clockid_ns;
> + char tstr[64], date[64];
> + struct timeval tod_ns;
> + clockid_t clockid;
> + struct tm ltime;
> + u64 ref;
> +
> + if (!ff->ph->env.clock.enabled) {
> + fprintf(fp, "# reference time disabled\n");
> + return;
> + }
> +
> + /* Compute TOD time. */
> + ref = ff->ph->env.clock.tod_ns;
> + tod_ns.tv_sec = ref / NSEC_PER_SEC;
> + ref -= tod_ns.tv_sec * NSEC_PER_SEC;
> + tod_ns.tv_usec = ref / NSEC_PER_USEC;
> +
> + /* Compute clockid time. */
> + ref = ff->ph->env.clock.clockid_ns;
> + clockid_ns.tv_sec = ref / NSEC_PER_SEC;
> + ref -= clockid_ns.tv_sec * NSEC_PER_SEC;
> + clockid_ns.tv_nsec = ref;
> +
> + clockid = ff->ph->env.clock.clockid;
> +
> + if (localtime_r(&tod_ns.tv_sec, &ltime) == NULL)
> + snprintf(tstr, sizeof(tstr), "<error>");
> + else {
> + strftime(date, sizeof(date), "%F %T", &ltime);
> + scnprintf(tstr, sizeof(tstr), "%s.%06d",
> + date, (int) tod_ns.tv_usec);
> + }
> +
> + fprintf(fp, "# clockid: %s (%u)\n", clockid_name(clockid), clockid);
> + fprintf(fp, "# reference time: %s = %ld.%06d (TOD) = %ld.%ld (%s)\n",

Shouldn't the last one be %ld.%09ld?

Thanks
Namhyung


> + tstr, tod_ns.tv_sec, (int) tod_ns.tv_usec,
> + clockid_ns.tv_sec, clockid_ns.tv_nsec,
> + clockid_name(clockid));
> +}
> +
> static void print_dir_format(struct feat_fd *ff, FILE *fp)
> {
> struct perf_session *session;
> @@ -2738,6 +2815,40 @@ static int process_clockid(struct feat_fd *ff,
> return 0;
> }
>
> +static int process_clock_data(struct feat_fd *ff,
> + void *_data __maybe_unused)
> +{
> + u32 data32;
> + u64 data64;
> +
> + /* version */
> + if (do_read_u32(ff, &data32))
> + return -1;
> +
> + if (data32 != 1)
> + return -1;
> +
> + /* clockid */
> + if (do_read_u32(ff, &data32))
> + return -1;
> +
> + ff->ph->env.clock.clockid = data32;
> +
> + /* TOD ref time */
> + if (do_read_u64(ff, &data64))
> + return -1;
> +
> + ff->ph->env.clock.tod_ns = data64;
> +
> + /* clockid ref time */
> + if (do_read_u64(ff, &data64))
> + return -1;
> +
> + ff->ph->env.clock.clockid_ns = data64;
> + ff->ph->env.clock.enabled = true;
> + return 0;
> +}
> +
> static int process_dir_format(struct feat_fd *ff,
> void *_data __maybe_unused)
> {
> @@ -3008,6 +3119,7 @@ const struct perf_header_feature_ops feat_ops[HEADER_LAST_FEATURE] = {
> FEAT_OPR(BPF_BTF, bpf_btf, false),
> FEAT_OPR(COMPRESSED, compressed, false),
> FEAT_OPR(CPU_PMU_CAPS, cpu_pmu_caps, false),
> + FEAT_OPR(CLOCK_DATA, clock_data, false),
> };
>
> struct header_print_data {
> diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h
> index 650bd1c7a99b..2aca71763ecf 100644
> --- a/tools/perf/util/header.h
> +++ b/tools/perf/util/header.h
> @@ -44,6 +44,7 @@ enum {
> HEADER_BPF_BTF,
> HEADER_COMPRESSED,
> HEADER_CPU_PMU_CAPS,
> + HEADER_CLOCK_DATA,
> HEADER_LAST_FEATURE,
> HEADER_FEAT_BITS = 256,
> };
> --
> 2.25.4

\
 
 \ /
  Last update: 2020-08-03 05:58    [W:0.192 / U:0.020 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site