[PATCH v2 6/9] trace2: add timer events to perf and event target formats
- From
- Jeff Hostetler via GitGitGadget <gitgitgadget@gmail.com>
- Date
- Dec 28, 2021, 19:36 UTC
- Message-ID
- <62a5c8b035671e8b5df6121660e657ba216d90fc.1640720202.git.gitgitgadget@gmail.com>
- In-Reply-To
- <pull.1099.v2.git.1640720202.gitgitgadget@gmail.com>
From: Jeff Hostetler <jeffhost@microsoft.com>
Teach Trace2 "perf" and "event" formats to handle "timer" events for stopwatch timers. Update API documentation accordingly.
In a future commit, stopwatch timers will be added to the Trace2 API and it will emit these "timer" events.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> --- Documentation/technical/api-trace2.txt | 23 ++++++++++++++++++++ trace2/tr2_tgt.h | 25 ++++++++++++++++++++++ trace2/tr2_tgt_event.c | 29 ++++++++++++++++++++++++++ trace2/tr2_tgt_normal.c | 1 + trace2/tr2_tgt_perf.c | 27 ++++++++++++++++++++++++ 5 files changed, 105 insertions(+)
diff --git a/Documentation/technical/api-trace2.txt b/Documentation/technical/api-trace2.txt index bb13ca3db8b..351d140879e 100644 --- a/Documentation/technical/api-trace2.txt +++ b/Documentation/technical/api-trace2.txt @@ -815,6 +815,29 @@ The "value" field may be an integer or a string. } ------------ +`"timer"`:: + This event is generated at the end of the program and contains + statistics for a global stopwatch timer. ++ +------------ +{ + "event":"timer", + ... + "name":"test", # timer name + "count":42, # number of start+stop intervals + "ns_total":1234, # sum of all intervals in nanoseconds + "ns_min":11, # shortest interval in nanoseconds + "ns_max":789, # longest interval in nanoseconds +} +------------ ++ +Stopwatch timer data is independently collected by each thread and then +aggregated for the whole program, so the total time reported here +may exceed the "atexit" elapsed time of the program. ++ +Timer events may represent an individual thread or a summation across +the entire program. Summation events will have a unique thread name. + == Example Trace2 API Usage Here is a hypothetical usage of the Trace2 API showing the intended diff --git a/trace2/tr2_tgt.h b/trace2/tr2_tgt.h index 65f94e15748..a41f91d09b5 100644 --- a/trace2/tr2_tgt.h +++ b/trace2/tr2_tgt.h @@ -96,6 +96,30 @@ typedef void(tr2_tgt_evt_printf_va_fl_t)(const char *file, int line, uint64_t us_elapsed_absolute, const char *fmt, va_list ap); +/* + * Stopwatch timer event. This function writes the previously accumulated + * stopwatch timer values to the event streams. Unlike other Trace2 API + * events, this is decoupled from the data collection. + * + * This does not take a (file,line) pair because a timer event reports + * the cumulative time spend in the timer over a series of intervals + * -- it does not represent a single usage (like region or data events + * do). + * + * The thread name is optional. If non-null it will override the + * value inherited from the caller's thread local storage. This + * allows timer data to be aggregated and reported without associating + * it to a specific thread. + */ +typedef void(tr2_tgt_evt_timer_t)(uint64_t us_elapsed_absolute, + const char *thread_name, + const char *category, + const char *timer_name, + uint64_t interval_count, + uint64_t ns_total_time, + uint64_t ns_min_time, + uint64_t ns_max_time); + /* * "vtable" for a TRACE2 target. Use NULL if a target does not want * to emit that message. @@ -132,6 +156,7 @@ struct tr2_tgt { tr2_tgt_evt_data_fl_t *pfn_data_fl; tr2_tgt_evt_data_json_fl_t *pfn_data_json_fl; tr2_tgt_evt_printf_va_fl_t *pfn_printf_va_fl; + tr2_tgt_evt_timer_t *pfn_timer; }; /* clang-format on */ diff --git a/trace2/tr2_tgt_event.c b/trace2/tr2_tgt_event.c index 4ce50944298..fe89e80bb1a 100644 --- a/trace2/tr2_tgt_event.c +++ b/trace2/tr2_tgt_event.c @@ -615,6 +615,34 @@ static void fn_data_json_fl(const char *file, int line, } } +static void fn_timer(uint64_t us_elapsed_absolute, + const char *thread_name, + const char *category, + const char *timer_name, + uint64_t interval_count, + uint64_t ns_total_time, + uint64_t ns_min_time, + uint64_t ns_max_time) +{ + const char *event_name = "timer"; + struct json_writer jw = JSON_WRITER_INIT; + double t_abs = (double)us_elapsed_absolute / 1000000.0; + + jw_object_begin(&jw, 0); + event_fmt_prepare(event_name, __FILE__, __LINE__, NULL, &jw, thread_name); + jw_object_double(&jw, "t_abs", 6, t_abs); + jw_object_string(&jw, "name", timer_name); + jw_object_intmax(&jw, "count", interval_count); + jw_object_intmax(&jw, "ns_total", ns_total_time); + jw_object_intmax(&jw, "ns_min", ns_min_time); + jw_object_intmax(&jw, "ns_max", ns_max_time); + + jw_end(&jw); + + tr2_dst_write_line(&tr2dst_event, &jw.json); + jw_release(&jw); +} + struct tr2_tgt tr2_tgt_event = { &tr2dst_event, @@ -646,4 +674,5 @@ struct tr2_tgt tr2_tgt_event = { fn_data_fl, fn_data_json_fl, NULL, /* printf */ + fn_timer, }; diff --git a/trace2/tr2_tgt_normal.c b/trace2/tr2_tgt_normal.c index 58d9e430f05..23a7e78dcaa 100644 --- a/trace2/tr2_tgt_normal.c +++ b/trace2/tr2_tgt_normal.c @@ -355,4 +355,5 @@ struct tr2_tgt tr2_tgt_normal = { NULL, /* data */ NULL, /* data_json */ fn_printf_va_fl, + NULL, /* timer */ }; diff --git a/trace2/tr2_tgt_perf.c b/trace2/tr2_tgt_perf.c index c008fd08ae8..c07ffad1a32 100644 --- a/trace2/tr2_tgt_perf.c +++ b/trace2/tr2_tgt_perf.c @@ -555,6 +555,32 @@ static void fn_printf_va_fl(const char *file, int line, strbuf_release(&buf_payload); } +static void fn_timer(uint64_t us_elapsed_absolute, + const char *thread_name, + const char *category, + const char *timer_name, + uint64_t interval_count, + uint64_t ns_total_time, + uint64_t ns_min_time, + uint64_t ns_max_time) +{ + const char *event_name = "timer"; + struct strbuf buf_payload = STRBUF_INIT; + + strbuf_addf(&buf_payload, ("name:%s" + " count:%"PRIu64 + " ns_total:%"PRIu64 + " ns_min:%"PRIu64 + " ns_max:%"PRIu64), + timer_name, interval_count, ns_total_time, ns_min_time, + ns_max_time); + + perf_io_write_fl(__FILE__, __LINE__, event_name, NULL, + &us_elapsed_absolute, NULL, + category, &buf_payload, thread_name); + strbuf_release(&buf_payload); +} + struct tr2_tgt tr2_tgt_perf = { &tr2dst_perf, @@ -586,4 +612,5 @@ struct tr2_tgt tr2_tgt_perf = { fn_data_fl, fn_data_json_fl, fn_printf_va_fl, + fn_timer, };
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