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Date: Wed, 5 Aug 2015 09:18:10 +0200
From: Jiri Olsa <jolsa@...hat.com>
To: Kan Liang <kan.liang@...el.com>
Cc: acme@...nel.org, jolsa@...nel.org, namhyung@...nel.org,
ak@...ux.intel.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH RFC V8 1/4] perf,tools: per-event time support
On Tue, Aug 04, 2015 at 04:30:19AM -0400, Kan Liang wrote:
> From: Kan Liang <kan.liang@...el.com>
>
> This patchkit adds the ability to turn off time stamps per event.
> One usable case of partial time is to work with per-event callgraph to
> enable "PEBS threshold > 1" (https://lkml.org/lkml/2015/5/10/196), which
> can significantly reduce the sampling overhead.
> The event samples with time stamps off will not be ordered.
>
> Signed-off-by: Kan Liang <kan.liang@...el.com>
Acked-by: Jiri Olsa <jolsa@...nel.org>
thanks,
jirka
> ---
> tools/perf/Documentation/perf-record.txt | 4 +++-
> tools/perf/util/evsel.c | 14 +++++++++++---
> tools/perf/util/evsel.h | 2 ++
> tools/perf/util/parse-events.c | 12 ++++++++++++
> tools/perf/util/parse-events.h | 1 +
> tools/perf/util/parse-events.l | 1 +
> tools/perf/util/pmu.c | 2 +-
> 7 files changed, 31 insertions(+), 5 deletions(-)
>
> diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
> index ac41350..0d852d1 100644
> --- a/tools/perf/Documentation/perf-record.txt
> +++ b/tools/perf/Documentation/perf-record.txt
> @@ -49,7 +49,9 @@ OPTIONS
> These params can be used to overload default config values per event.
> Here is a list of the params.
> - 'period': Set event sampling period
> -
> + - 'time': Disable/enable time stamping. Acceptable values are 1 for
> + enabling time stamping. 0 for disabling time stamping.
> + The default is 1.
> Note: If user explicitly sets options which conflict with the params,
> the value set by the params will be overridden.
>
> diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> index 7d3acba..7febfe2 100644
> --- a/tools/perf/util/evsel.c
> +++ b/tools/perf/util/evsel.c
> @@ -587,15 +587,23 @@ perf_evsel__config_callgraph(struct perf_evsel *evsel,
> }
> }
>
> -static void apply_config_terms(struct perf_event_attr *attr __maybe_unused,
> - struct list_head *config_terms)
> +static void apply_config_terms(struct perf_evsel *evsel)
> {
> struct perf_evsel_config_term *term;
> + struct list_head *config_terms = &evsel->config_terms;
> + struct perf_event_attr *attr = &evsel->attr;
>
> list_for_each_entry(term, config_terms, list) {
> switch (term->type) {
> case PERF_EVSEL__CONFIG_TERM_PERIOD:
> attr->sample_period = term->val.period;
> + break;
> + case PERF_EVSEL__CONFIG_TERM_TIME:
> + if (term->val.time)
> + perf_evsel__set_sample_bit(evsel, TIME);
> + else
> + perf_evsel__reset_sample_bit(evsel, TIME);
> + break;
> default:
> break;
> }
> @@ -798,7 +806,7 @@ void perf_evsel__config(struct perf_evsel *evsel, struct record_opts *opts)
> * Apply event specific term settings,
> * it overloads any global configuration.
> */
> - apply_config_terms(attr, &evsel->config_terms);
> + apply_config_terms(evsel);
> }
>
> static int perf_evsel__alloc_fd(struct perf_evsel *evsel, int ncpus, int nthreads)
> diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
> index a7d2175..6a12908 100644
> --- a/tools/perf/util/evsel.h
> +++ b/tools/perf/util/evsel.h
> @@ -39,6 +39,7 @@ struct cgroup_sel;
> */
> enum {
> PERF_EVSEL__CONFIG_TERM_PERIOD,
> + PERF_EVSEL__CONFIG_TERM_TIME,
> PERF_EVSEL__CONFIG_TERM_MAX,
> };
>
> @@ -47,6 +48,7 @@ struct perf_evsel_config_term {
> int type;
> union {
> u64 period;
> + bool time;
> } val;
> };
>
> diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
> index 09bee93..a6cb9af 100644
> --- a/tools/perf/util/parse-events.c
> +++ b/tools/perf/util/parse-events.c
> @@ -603,6 +603,14 @@ do { \
> * attr->branch_sample_type = term->val.num;
> */
> break;
> + case PARSE_EVENTS__TERM_TYPE_TIME:
> + CHECK_TYPE_VAL(NUM);
> + if (term->val.num > 1) {
> + err->str = strdup("expected 0 or 1");
> + err->idx = term->err_val;
> + return -EINVAL;
> + }
> + break;
> case PARSE_EVENTS__TERM_TYPE_NAME:
> CHECK_TYPE_VAL(STR);
> break;
> @@ -650,6 +658,10 @@ do { \
> switch (term->type_term) {
> case PARSE_EVENTS__TERM_TYPE_SAMPLE_PERIOD:
> ADD_CONFIG_TERM(PERIOD, period, term->val.num);
> + break;
> + case PARSE_EVENTS__TERM_TYPE_TIME:
> + ADD_CONFIG_TERM(TIME, time, term->val.num);
> + break;
> default:
> break;
> }
> diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
> index 2063048..e6f9aacc 100644
> --- a/tools/perf/util/parse-events.h
> +++ b/tools/perf/util/parse-events.h
> @@ -63,6 +63,7 @@ enum {
> PARSE_EVENTS__TERM_TYPE_NAME,
> PARSE_EVENTS__TERM_TYPE_SAMPLE_PERIOD,
> PARSE_EVENTS__TERM_TYPE_BRANCH_SAMPLE_TYPE,
> + PARSE_EVENTS__TERM_TYPE_TIME,
> };
>
> struct parse_events_term {
> diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
> index 13cef3c..f542750 100644
> --- a/tools/perf/util/parse-events.l
> +++ b/tools/perf/util/parse-events.l
> @@ -183,6 +183,7 @@ config2 { return term(yyscanner, PARSE_EVENTS__TERM_TYPE_CONFIG2); }
> name { return term(yyscanner, PARSE_EVENTS__TERM_TYPE_NAME); }
> period { return term(yyscanner, PARSE_EVENTS__TERM_TYPE_SAMPLE_PERIOD); }
> branch_type { return term(yyscanner, PARSE_EVENTS__TERM_TYPE_BRANCH_SAMPLE_TYPE); }
> +time { return term(yyscanner, PARSE_EVENTS__TERM_TYPE_TIME); }
> , { return ','; }
> "/" { BEGIN(INITIAL); return '/'; }
> {name_minus} { return str(yyscanner, PE_NAME); }
> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> index 7bcb8c3..b615cdf 100644
> --- a/tools/perf/util/pmu.c
> +++ b/tools/perf/util/pmu.c
> @@ -607,7 +607,7 @@ static char *formats_error_string(struct list_head *formats)
> {
> struct perf_pmu_format *format;
> char *err, *str;
> - static const char *static_terms = "config,config1,config2,name,period,branch_type\n";
> + static const char *static_terms = "config,config1,config2,name,period,branch_type,time\n";
> unsigned i = 0;
>
> if (!asprintf(&str, "valid terms:"))
> --
> 1.8.3.1
>
--
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