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Date: Sun, 12 Dec 2010 22:32:05 +0100
From: Frederic Weisbecker <fweisbec@...il.com>
To: David Ahern <daahern@...co.com>
Cc: linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
Arnaldo Carvalho de Melo <acme@...hat.com>
Subject: Re: [PATCH 2/2] perf tools: Add option to show time history of
event samples
On Tue, Dec 07, 2010 at 06:54:45PM -0700, David Ahern wrote:
> Add a timehist option to perf record to save cpu and kernel timestamp
> with each sample.
>
> Add timehist option to perf report to display a pretty-print format
> of the timestamp, cpu, and event data each event rather than
> generating a histogram. The timehist option leverages the reference
> timestamp from the perf header to correlate kernel timestamps to
> time-of-day which allows correlating with external (non-perf)
> log files.
>
> As an example, consider recording context switches:
> perf record -e cs -c 1 -ga --timehist
>
> Today the 'perf report -D' option gives output in the form
> 0 182392227877 0x17d8f8 [0xd8]: PERF_RECORD_SAMPLE(IP, 1): \
> 1861/1861: 0xffffffff810348d2 period: 2057672
> ... chain: nr:21
> ..... 0: ffffffffffffff80
> ..... 1: ffffffff810348d2
> ..... 2: ffffffff8139c02b
> ..... 3: ffffffffa004b4a3
> ..... 4: ffffffff8139c79c
> ..... 5: ffffffff8139c83d
> ..... 6: ffffffffa004b43f
> ..... 7: ffffffffa00ec135
> ..... 8: ffffffffa00ec214
> ..... 9: ffffffffa00f01ec
> ..... 10: ffffffffa00f0439
> ..... 11: ffffffffa00d6e8b
> ..... 12: ffffffff8110b763
> ..... 13: ffffffff8110b883
> ..... 14: ffffffff8110ddcd
> ..... 15: ffffffff8110e45d
> ..... 16: ffffffff81101f36
> ..... 17: ffffffff81101ff3
> ..... 18: ffffffff81002c82
> ..... 19: fffffffffffffe00
> ..... 20: 00002acfd31ce050
> ... thread: cc1:1861
> ...... dso: /lib/modules/2.6.37-rc5/build/vmlinux
>
> With the timehist option 'perf report --timehist' displays the same sample as
> (lines wrapped to < 80 and truncated here):
>
> 17:11:10.174502 182392227877 0 cc1 1861 \
> ffffffff810348d2 perf_event_task_sched_out ([kernel.kallsyms])
> 17:11:10.174502 182392227877 0 cc1 1861 \
> ffffffff8139c02b schedule ([kernel.kallsyms])
> 17:11:10.174502 182392227877 0 cc1 1861 \
> ffffffffa004b4a3 rpc_wait_bit_killable (/lib/modules/2.6.37-rc5/...
> 17:11:10.174502 182392227877 0 cc1 1861 \
> ffffffff8139c79c __wait_on_bit ([kernel.kallsyms])
> 17:11:10.174502 182392227877 0 cc1 1861 \
> ffffffff8139c83d out_of_line_wait_on_bit ([kernel.kallsyms])
> 17:11:10.174502 182392227877 0 cc1 1861 \
> ffffffffa004b43f __rpc_wait_for_completion_task (/lib/modules/...
> 17:11:10.174502 182392227877 0 cc1 1861 \
> ffffffffa00ec135 nfs4_wait_for_completion_rpc_task (/lib/modules/...
> 17:11:10.174502 182392227877 0 cc1 1861 \
> ffffffffa00ec214 nfs4_run_open_task (/lib/modules/2.6.37-rc5/...
> 17:11:10.174502 182392227877 0 cc1 1861 \
> ffffffffa00f01ec nfs4_do_open.clone.21 (/lib/modules/2.6.37-rc5/...
> 17:11:10.174502 182392227877 0 cc1 1861 \
> ffffffffa00f0439 nfs4_atomic_open (/lib/modules/2.6.37-rc5/...
> 17:11:10.174502 182392227877 0 cc1 1861 \
> ffffffffa00d6e8b nfs_open_revalidate (/lib/modules/2.6.37-rc5/...
> 17:11:10.174502 182392227877 0 cc1 1861 \
> ffffffff8110b763 do_revalidate ([kernel.kallsyms])
> 17:11:10.174502 182392227877 0 cc1 1861 \
> ffffffff8110b883 do_lookup ([kernel.kallsyms])
> 17:11:10.174502 182392227877 0 cc1 1861 \
> ffffffff8110ddcd do_last ([kernel.kallsyms])
> 17:11:10.174502 182392227877 0 cc1 1861 \
> ffffffff8110e45d do_filp_open ([kernel.kallsyms])
> 17:11:10.174502 182392227877 0 cc1 1861 \
> ffffffff81101f36 do_sys_open ([kernel.kallsyms])
> 17:11:10.174502 182392227877 0 cc1 1861 \
> ffffffff81101ff3 sys_open ([kernel.kallsyms])
> 17:11:10.174502 182392227877 0 cc1 1861 \
> ffffffff81002c82 system_call ([kernel.kallsyms])
> 17:11:10.174502 182392227877 0 cc1 1861 \
> 2acfd31ce050 __GI___libc_open (/lib64/libc-2.12.90.so)
>
> While the line lengths are horrible for a git commit message and email,
> the data is indispensable. It allows you to see each schedule out point,
> where the process is when it gets scheduled out and, with additional
> processing on the timehist output, time between schedule-in events and
> time on the processor.
>
> Signed-off-by: David Ahern <daahern@...co.com>
> ---
> tools/perf/builtin-record.c | 8 +++
> tools/perf/builtin-report.c | 131 ++++++++++++++++++++++++++++++++++++++++++-
> 2 files changed, 137 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index 699dd21..cf30c98 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -51,6 +51,7 @@ static int realtime_prio = 0;
> static bool raw_samples = false;
> static bool sample_id_all_avail = true;
> static bool system_wide = false;
> +static bool time_history = false;
> static pid_t target_pid = -1;
> static pid_t target_tid = -1;
> static pid_t *all_tids = NULL;
> @@ -288,6 +289,11 @@ static void create_counter(int counter, int cpu)
> if (sample_time)
> attr->sample_type |= PERF_SAMPLE_TIME;
>
> + if (time_history) {
> + attr->sample_type |= PERF_SAMPLE_TIME;
> + attr->sample_type |= PERF_SAMPLE_CPU;
> + }
> +
> if (raw_samples) {
> attr->sample_type |= PERF_SAMPLE_TIME;
> attr->sample_type |= PERF_SAMPLE_RAW;
> @@ -863,6 +869,8 @@ const struct option record_options[] = {
> "do not update the buildid cache"),
> OPT_BOOLEAN('B', "no-buildid", &no_buildid,
> "do not collect buildids in perf.data"),
> + OPT_BOOLEAN(0, "timehist", &time_history,
> + "collect data for time history report"),
> OPT_END()
> };
It seems you should only to the gettimeofday() / clock_gettime()
record if you have time_history set?
Thanks.
>
> diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
> index 904519f..bcde3c2 100644
> --- a/tools/perf/builtin-report.c
> +++ b/tools/perf/builtin-report.c
> @@ -35,6 +35,7 @@ static char const *input_name = "perf.data";
> static bool force, use_tui, use_stdio;
> static bool hide_unresolved;
> static bool dont_use_callchains;
> +static bool time_history;
>
> static bool show_threads;
> static struct perf_read_values show_threads_values;
> @@ -124,6 +125,117 @@ out_free_syms:
> return err;
> }
>
> +static const char *timestr(u64 timestamp, struct perf_session *session)
> +{
> + struct tm ltime;
> + u64 dt;
> + struct timeval tv_dt, tv_res;
> + static char tstr[64];
> +
> + dt = timestamp - session->header.nsec_ref;
> + tv_dt.tv_sec = (time_t) (dt / NSEC_PER_SEC);
> + tv_dt.tv_usec = (suseconds_t) ((dt - tv_dt.tv_sec * NSEC_PER_SEC) / 1000);
> +
> + timeradd(&session->header.tv_ref, &tv_dt, &tv_res);
> +
> + if ((session->header.nsec_ref == 0) ||
> + (localtime_r(&tv_res.tv_sec, <ime) == NULL)) {
> + snprintf(tstr, sizeof(tstr), "00:00:00.000000 %16Ld", timestamp);
> + } else {
> + char date[64];
> + strftime(date, sizeof(date), "%H:%M:%S", <ime);
> + snprintf(tstr, sizeof(tstr), "%s.%06ld %16Ld",
> + date, tv_res.tv_usec, timestamp);
> + }
> +
> + return tstr;
> +}
> +
> +#define TIMEHIST_FMT "%32s %3d %-16s %5d %16Lx %s (%s)\n"
> +
> +static void timehist_header(void)
> +{
> + printf("%32s %3s %-16s %5s %16s %s (%s)\n",
> + " Time-of-Day Kernel Timestamp",
> + "cpu", "Command Name", "PID",
> + " IP ", "Symbol Name", "DSO Name");
> +}
> +
> +static int perf_session__print_sample(struct perf_session *session,
> + struct addr_location *al,
> + struct sample_data *data)
> +{
> + static int show_timehist_error = 1;
> + u64 timestamp = 0;
> + struct map_symbol *syms = NULL;
> + struct symbol *parent = NULL;
> + const char *tstr;
> + bool need_spacer = false;
> +
> + if (show_timehist_error && ((data->cpu == (u32) -1) ||
> + !(session->sample_type & PERF_SAMPLE_TIME))) {
> + pr_err("Data for time history missing in perf event samples.\n"
> + "Did you record with --timehist option?\n");
> + show_timehist_error = 0;
> + }
> +
> + if (session->sample_type & PERF_SAMPLE_TIME)
> + timestamp = data->time;
> +
> + tstr = timestr(timestamp, session);
> +
> +
> + if ((symbol_conf.use_callchain) && data->callchain) {
> + u64 i;
> +
> + syms = perf_session__resolve_callchain(session, al->thread,
> + data->callchain, &parent);
> + if (syms == NULL)
> + return -ENOMEM;
> +
> + for (i = 0; i < data->callchain->nr; ++i) {
> + const char *symname = "", *dsoname = "";
> +
> + if (data->callchain->ips[i] >= PERF_CONTEXT_MAX)
> + continue;
> +
> + if (syms[i].sym && syms[i].sym->name)
> + symname = syms[i].sym->name;
> + else if (hide_unresolved)
> + continue;
> +
> + if (syms[i].map && syms[i].map->dso &&
> + syms[i].map->dso->name)
> + dsoname = syms[i].map->dso->name;
> + else if (hide_unresolved)
> + continue;
> +
> + printf(TIMEHIST_FMT,
> + tstr, data->cpu,
> + al->thread->comm, al->thread->pid,
> + data->callchain->ips[i], symname, dsoname);
> +
> + need_spacer = true;
> + }
> +
> + free(syms);
> +
> + } else {
> + printf(TIMEHIST_FMT,
> + tstr, data->cpu,
> + al->thread->comm, al->thread->pid, al->addr,
> + al->sym->name, al->map->dso->name);
> +
> + need_spacer = true;
> + }
> +
> + /* put a gap between records */
> + if (need_spacer)
> + printf("\n");
> +
> + return 0;
> +}
> +
> static int add_event_total(struct perf_session *session,
> struct sample_data *data,
> struct perf_event_attr *attr)
> @@ -165,7 +277,9 @@ static int process_sample_event(event_t *event, struct sample_data *sample,
> if (al.filtered || (hide_unresolved && al.sym == NULL))
> return 0;
>
> - if (perf_session__add_hist_entry(session, &al, sample)) {
> + if (time_history) {
> + perf_session__print_sample(session, &al, sample);
> + } else if (perf_session__add_hist_entry(session, &al, sample)) {
> pr_debug("problem incrementing symbol period, skipping event\n");
> return -1;
> }
> @@ -319,6 +433,14 @@ static int __cmd_report(void)
> if (ret)
> goto out_delete;
>
> + if (time_history) {
> + if (!session->header.nsec_ref) {
> + pr_err("Reference timestamp missing in perf.data file.\n"
> + "Cannot convert kernel timestamps to time-of-day.\n");
> + }
> + timehist_header();
> + }
> +
> ret = perf_session__process_events(session, &event_ops);
> if (ret)
> goto out_delete;
> @@ -334,6 +456,9 @@ static int __cmd_report(void)
> if (verbose > 2)
> perf_session__fprintf_dsos(session, stdout);
>
> + if (time_history)
> + goto out_delete;
> +
> next = rb_first(&session->hists_tree);
> while (next) {
> struct hists *hists;
> @@ -479,6 +604,8 @@ static const struct option options[] = {
> "columns '.' is reserved."),
> OPT_BOOLEAN('U', "hide-unresolved", &hide_unresolved,
> "Only display entries resolved to a symbol"),
> + OPT_BOOLEAN(0, "timehist", &time_history,
> + "Dump time history of event samples"),
> OPT_END()
> };
>
> @@ -486,7 +613,7 @@ int cmd_report(int argc, const char **argv, const char *prefix __used)
> {
> argc = parse_options(argc, argv, options, report_usage, 0);
>
> - if (use_stdio)
> + if (use_stdio || time_history)
> use_browser = 0;
> else if (use_tui)
> use_browser = 1;
> --
> 1.7.2.3
>
> --
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