From: Kan Liang <kan.li...@intel.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.li...@intel.com>
---
tools/perf/Documentation/perf-record.txt | 4 +++-
tools/perf/builtin-record.c | 7 ++++++-
tools/perf/builtin-trace.c | 1 +
tools/perf/util/evsel.c | 30 ++++++++++++++++++++++++++++--
tools/perf/util/parse-events.c | 11 +++++++++++
tools/perf/util/parse-events.h | 3 +++
tools/perf/util/parse-events.l | 1 +
tools/perf/util/pmu.c | 2 +-
8 files changed, 54 insertions(+), 5 deletions(-)
diff --git a/tools/perf/Documentation/perf-record.txt
b/tools/perf/Documentation/perf-record.txt
index 5b47b2c..df47907 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 set event defaults.
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/builtin-record.c b/tools/perf/builtin-record.c
index eae6510..a06d8c2 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -956,7 +956,6 @@ const char * const *record_usage = __record_usage;
*/
static struct record record = {
.opts = {
- .sample_time = true,
.mmap_pages = UINT_MAX,
.user_freq = UINT_MAX,
.user_interval = ULLONG_MAX,
@@ -1139,6 +1138,12 @@ int cmd_record(int argc, const char **argv, const char
*prefix __maybe_unused)
goto out_symbol_exit;
}
+ /* If no one set time, let time = true as default */
+ if (!rec->opts.sample_time_set && !time_term_detected) {
+ rec->opts.sample_time = true;
+ rec->opts.sample_time_set = true;
+ }
+
if (rec->opts.target.tid && !rec->opts.no_inherit_set)
rec->opts.no_inherit = true;
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 0ebf55b..469d316 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -2899,6 +2899,7 @@ int cmd_trace(int argc, const char **argv, const char
*prefix __maybe_unused)
if (trace.trace_pgfaults) {
trace.opts.sample_address = true;
trace.opts.sample_time = true;
+ trace.opts.sample_time_set = true;
}
if (trace.evlist->nr_entries > 0)
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 83c0803..34f9cfd 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -619,10 +619,35 @@ void perf_evsel__config(struct perf_evsel *evsel, struct
record_opts *opts)
struct perf_event_attr *attr = &evsel->attr;
int track = evsel->tracking;
bool per_cpu = opts->target.default_per_cpu && !opts->target.per_thread;
+ bool sample_time = opts->sample_time;
attr->sample_id_all = perf_missing_features.sample_id_all ? 0 : 1;
attr->inherit = !opts->no_inherit;
+ /*
+ * If user doesn't explicitly set time option,
+ * let event attribute decide.
+ */
+
+ if (!opts->sample_time_set) {
+ if (attr->sample_type & PERF_SAMPLE_TIME)
+ sample_time = true;
+ else
+ sample_time = false;
+ }
+
+ /*
+ * Event parsing doesn't check the availability
+ * Clear the bit which event parsing may be set.
+ * Let following code check and reset if available
+ *
+ * Also, the sample size may be caculated mistakenly,
+ * because event parsing may set the PERF_SAMPLE_TIME.
+ * Remove the size which add in perf_evsel__init
+ */
+ if (attr->sample_type & PERF_SAMPLE_TIME)
+ perf_evsel__reset_sample_bit(evsel, TIME);
+
perf_evsel__set_sample_bit(evsel, IP);
perf_evsel__set_sample_bit(evsel, TID);
@@ -705,14 +730,15 @@ void perf_evsel__config(struct perf_evsel *evsel, struct
record_opts *opts)
/*
* When the user explicitely disabled time don't force it here.
*/
- if (opts->sample_time &&
+ if (sample_time &&
(!perf_missing_features.sample_id_all &&
(!opts->no_inherit || target__has_cpu(&opts->target) || per_cpu ||
opts->sample_time_set)))
perf_evsel__set_sample_bit(evsel, TIME);
if (opts->raw_samples && !evsel->no_aux_samples) {
- perf_evsel__set_sample_bit(evsel, TIME);
+ if (sample_time)
+ perf_evsel__set_sample_bit(evsel, TIME);
perf_evsel__set_sample_bit(evsel, RAW);
perf_evsel__set_sample_bit(evsel, CPU);
}
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index a71eeb2..c9981df 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -25,6 +25,9 @@
#ifdef PARSER_DEBUG
extern int parse_events_debug;
#endif
+
+bool time_term_detected = false;
+
int parse_events_parse(void *data, void *scanner);
static struct perf_pmu_event_symbol *perf_pmu_events_list;
@@ -598,6 +601,14 @@ do {
\
* attr->branch_sample_type = term->val.num;
*/
break;
+ case PARSE_EVENTS__TERM_TYPE_TIME:
+ CHECK_TYPE_VAL(NUM);
+ if (term->val.num > 1)
+ return -EINVAL;
+ time_term_detected = true;
+ if (term->val.num == 1)
+ attr->sample_type |= PERF_SAMPLE_TIME;
+ break;
case PARSE_EVENTS__TERM_TYPE_NAME:
CHECK_TYPE_VAL(STR);
break;
diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
index 131f29b..1083478 100644
--- a/tools/perf/util/parse-events.h
+++ b/tools/perf/util/parse-events.h
@@ -22,6 +22,8 @@ struct tracepoint_path {
struct tracepoint_path *next;
};
+extern bool time_term_detected;
+
extern struct tracepoint_path *tracepoint_id_to_path(u64 config);
extern struct tracepoint_path *tracepoint_name_to_path(const char *name);
extern bool have_tracepoints(struct list_head *evlist);
@@ -62,6 +64,7 @@ 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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