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perf tools: Per-event time support

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This patchkit adds the ability to turn off time stamps per event.

One usaful case for 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@intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1438677022-34296-2-git-send-email-kan.liang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Kan Liang 2015-08-04 04:30:19 -04:00 committed by Arnaldo Carvalho de Melo
parent 34221118cb
commit 3206771239
7 changed files with 31 additions and 5 deletions
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4
tools/perf/Documentation/perf-record.txt
View File

@ -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.

14
tools/perf/util/evsel.c
View File

@ -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)

2
tools/perf/util/evsel.h
View File

@ -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;
};

12
tools/perf/util/parse-events.c
View File

@ -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;
}

1
tools/perf/util/parse-events.h
View File

@ -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 {

1
tools/perf/util/parse-events.l
View File

@ -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); }

2
tools/perf/util/pmu.c
View File

@ -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:"))