From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx> Add man pages for: traceeval_delta_create() traceeval_delta_create_size() traceeval_delta_start() traceeval_delta_start_size() traceeval_delta_stop() traceeval_delta_stop_size() traceeval_delta_continue() traceeval_delta_continue_size() Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx> --- Documentation/libtraceeval-delta-init.txt | 470 ++++++++++++++++++++++ Documentation/libtraceeval.txt | 40 ++ 2 files changed, 510 insertions(+) create mode 100644 Documentation/libtraceeval-delta-init.txt diff --git a/Documentation/libtraceeval-delta-init.txt b/Documentation/libtraceeval-delta-init.txt new file mode 100644 index 000000000000..0ae5fc629880 --- /dev/null +++ b/Documentation/libtraceeval-delta-init.txt @@ -0,0 +1,470 @@ +libtraceeval(3) +=============== + +NAME +---- +traceeval_delta_create, traceeval_delta_create_size, +traceeval_delta_start, traceeval_delta_start_size, traceeval_delta_stop, +traceeval_delta_stop_size, traceeval_delta_continue, traceeval_delta_continue_size +- Create and start/stop a traceeval_delta instance + +SYNOPSIS +-------- +[verse] +-- +*#include <traceeval.h>* + +int *traceeval_delta_create*(struct traceeval pass:[*]_teval_, + struct traceeval_type pass:[*]_keys_, + struct traceeval_type pass:[*]_vals_); +int *traceeval_delta_create_size*(struct traceeval pass:[*]_teval_, + struct traceeval_type pass:[*]_keys_, + struct traceeval_type pass:[*]_vals_, + size_t _nr_keys_, size_t _nr_vals_); + +int *traceeval_delta_start*(struct traceeval pass:[*]_teval_, + const struct traceeval_data pass:[*]_keys_, + const struct traceeval_data pass:[*]_vals_, + unsigned long long _timestamp_); +int *traceeval_delta_start_size*(struct traceeval pass:[*]_teval_, + const struct traceeval_data pass:[*]_keys_, size_t _nr_keys_, + const struct traceeval_data pass:[*]_vals_, size_t _nr_vals_, + unsigned long long _timestamp_); + +int *traceeval_delta_stop*(struct traceeval pass:[*]_teval_, + const struct traceeval_data pass:[*]_keys_, + const struct traceeval_data pass:[**]_results_, + unsigned long long _timestamp_, + unsigned long long *_delta_, + unsigned long long *_start_timestamp_); +int *traceeval_delta_stop_size*(struct traceeval pass:[*]_teval_, + const struct traceeval_data pass:[*]_keys_, size_t _nr_keys_, + const struct traceeval_data pass:[**]_results_, + unsigned long long _timestamp_, + unsigned long long *_delta_, + unsigned long long *_start_timestamp_); + +int *traceeval_delta_continue*(struct traceeval pass:[*]_teval_, + const struct traceeval_data pass:[*]_keys_, + const struct traceeval_data pass:[*]_vals_, + unsigned long long _timestamp_); +int *traceeval_delta_continue_size*(struct traceeval pass:[*]_teval_, + const struct traceeval_data pass:[*]keys, size_t _nr_keys_, + const struct traceeval_data pass:[*]_vals_, size_t _nr_vals_, + unsigned long long _timestamp_); +-- + +DESCRIPTION +----------- +The traceeval handles mapping keys and values for various events. One common use case +is to attach two events together to create a delta between their associated timestamps +and insert that information into a traceeval along with information from both the +starting event as well as the ending event. + +Since the above is very common, the traceeval_delta is used to facilitate this approach. +The traceeval_delta is a specialized traceeval that is designed to keep track of +the timestamps and deltas and pass values from the starting event to the stopping event. + +The *traceeval_delta_create()* creates a helper to the attached _teval_. It +takes _keys_ and _vals_ just like *traceeval_init*(3) but these _keys_ and _vals_ +are unrelated to the keys and vals associated to the attached _teval_. The _keys_ +are used to map fields of two events to be able to match a stopping event to the +corresponding starting event. The _vals_ is used to store data from the starting +event to pass over to the stopping event that can then be used to add information +to the _teval_. + +The _keys_ and _vals_ passed to *traceeval_delta_create()* must be a static array. If +dynamically sized arrays are to be required, then *traceeval_delta_create_size()* can be +used and the caller can pass in _nr_keys_ to denote how many _keys_ are being passed in +as well as _nr_vals_ to denote how many _vals_ are passed in (0 for NULL). + +When the starting event is encountered, *traceeval_delta_start()* is called with the +associated _teval_ and _keys_ that hold information about the starting event that will +be used to map this event to the stopping event. The _vals_ array will hold any +data about the starting event that should be passed to the ending event (or NULL if +unused). The _timestamp_ denotes the time that this event happened. The _timestamp_ +will be used at the stopping event to calculate a delta between the two events. + +When the stopping event is encountered, *traceeval_delta_stop()* is called with +the associated _teval_ and _keys_ that hold an array of fields that are to match +the keys passed to *traceeval_delta_start()*. If vals were specified for the delta +element, then _results_ will hold an array that has the data stored into the vals +array of *traceeval_delta_start()*. The _timestamp_ holds the time of the stopping +event and will be used for calculating _delta_, as _delta_ is simply the timestamp +passed to *traceeval_delta_start()* subtracted from _timestamp_. The timestamp +from the starting event will be stored in _start_timestamp_. Note, that _delta_, +_results_ and _start_timestamp_ are all optional and may be NULL if not needed. + +There's some cases where there may be more than one starting event, and the first +starting event is to be required for starting the timings and any new starting event +that happens before an ending event occurs should be ignored. In this case, +*traceeval_delta_continue()* is used. It acts the same as *traceeval_delta_start()* +except that if the matching _keys_ have not encountered a *traceeval_delta_stop()* +since a previous *traceeval_delta_start()* or *traceeval_delta_continue()* then +it will simply be ignored (Both the _timestamp_ and the _vals_ will be dropped). + +To describe one use case for this, if the runtime of a CPU is being recorded, +and anytime a task is scheduled on the CPU, it is considered a starting event, +but the delta should only be used when the CPU switches from idle to a running task, +*traceeval_delta_continue()* can be used whenever a task is scheduled on the CPU +and *traceeval_delta_stop()* can be used when the CPU goes idle. Only the first +occurrence of a task scheduling on the CPU will start the timing. If a task +is scheduled on the CPU when another task was already running, no update should +be made. If *traceeval_delta_start()* is used, the timestamp of the start event +will be that of the time the new task came onto the CPU preempting the previous +task and that would only show the runtime of the last task and not how long the +CPU itself was running tasks. + +*traceeval_delta_start()*, *traceeval_delta_stop()* and *traceeval_delta_continue()* +must have their _keys_ and _vals_ be static arrays. If a dynamic array is required +then their corresponding functions that end with "*_size()*" must be used to +specify the size of _keys_ with _nr_keys_ and _vals_ with _nr_vals_. + +RETURN VALUE +------------ +The *traceeval_delta_create()* and *traceeval_delta_create_size()* both return a 0 +on success and -1 on error. + +The *traceeval_delta_start()*, *traceeval_delta_start_size()*, *traceeval_delta_continue()* +and *traceeval_delta_continue_size()* return 0 on success and -1 on error. + +The *traceeval_delta_stop()* and *traceeval_delta_stop_size()* return 1 if there was +a corresponding start event found via the passed in _keys_, 0 if a corresponding +event was not found and -1 on error. + +EXAMPLE +------- +[source,c] +-- +#include <trace-cmd.h> +#include <traceeval.h> + +static struct traceeval_type task_delta_types[] = { + { + .name = "PID", + .type = TRACEEVAL_TYPE_NUMBER, + } +}; + +static struct traceeval_type task_delta_val_types[] = { + { + .name = "COMM", + .type = TRACEEVAL_TYPE_STRING, + } +}; + +static void start_task(struct traceeval *teval, int pid, const char *comm, + unsigned long long ts) +{ + struct traceeval_data keys[1]; + struct traceeval_data vals[1]; + + TRACEEVAL_SET_NUMBER(keys[0], pid); + TRACEEVAL_SET_CSTRING(vals[0], comm); + + if (traceeval_delta_start(teval, keys, vals, ts) < 0) + printf("FAILED\n"); +} + +static int stop_task(struct traceeval *teval, int pid, const char **comm, + unsigned long long ts, unsigned long long *delta) +{ + const struct traceeval_data *results; + struct traceeval_data keys[1]; + int ret; + + TRACEEVAL_SET_NUMBER(keys[0], pid); + + ret = traceeval_delta_stop(teval, keys, &results, ts, delta, NULL); + if (ret < 1) + return ret; + + if (comm) + *comm = results[0].string; + + traceeval_results_release(teval, results); + return 1; +} + +static struct traceeval_type task_types[] = { + { + .name = "COMM", + .type = TRACEEVAL_TYPE_STRING, + }, + { + .name = "PID", + .type = TRACEEVAL_TYPE_NUMBER, + } +}; + +static void insert_task(struct traceeval *teval, const char *comm, int pid, + unsigned long long delta, unsigned long long ts) +{ + struct traceeval_data keys[2]; + struct traceeval_data vals[1]; + + TRACEEVAL_SET_CSTRING(keys[0], comm); + TRACEEVAL_SET_NUMBER(keys[1], pid); + + TRACEEVAL_SET_DELTA(vals[0], delta, ts); + + traceeval_insert(teval, keys, vals); +} + +static struct traceeval_type cpu_delta_types[] = { + { + .name = "CPU", + .type = TRACEEVAL_TYPE_NUMBER, + } +}; + +static void start_cpu(struct traceeval *teval, int cpu, unsigned long long ts) +{ + struct traceeval_data keys[1]; + + TRACEEVAL_SET_NUMBER(keys[0], cpu); + + if (traceeval_delta_continue(teval, keys, NULL, ts) < 0) + printf("FAILED\n"); +} + +static int stop_cpu(struct traceeval *teval, int cpu, + unsigned long long ts, unsigned long long *delta) +{ + struct traceeval_data keys[1]; + int ret; + + TRACEEVAL_SET_NUMBER(keys[0], cpu); + + ret = traceeval_delta_stop(teval, keys, NULL, ts, delta, NULL); + if (ret < 1) + return ret; + return 1; +} + +static struct traceeval_type cpu_types[] = { + { + .name = "CPU", + .type = TRACEEVAL_TYPE_NUMBER, + } +}; + +static struct traceeval_type delta_type[] = { + { + .name = "delta", + .type = TRACEEVAL_TYPE_DELTA, + } +}; + +static void insert_cpu(struct traceeval *teval, int cpu, + unsigned long long delta, unsigned long long ts) +{ + struct traceeval_data keys[1]; + struct traceeval_data vals[1]; + + TRACEEVAL_SET_NUMBER(keys[0], cpu); + + TRACEEVAL_SET_DELTA(vals[0], delta, ts); + + traceeval_insert(teval, keys, vals); +} + +struct data { + struct traceeval *teval_tasks; + struct traceeval *teval_cpus; +}; + +static struct tep_format_field *get_field(struct tep_event *event, const char *name) +{ + static struct tep_format_field *field; + + field = tep_find_field(event, name); + if (!field) { + fprintf(stderr, "Could not find field %s for %s", name, event->name); + exit(-1); + } + + return field; +} + +static int switch_func(struct tracecmd_input *handle, struct tep_event *event, + struct tep_record *record, int cpu, void *d) +{ + static struct tep_format_field *next_comm; + static struct tep_format_field *prev_pid; + static struct tep_format_field *next_pid; + struct data *data = d; + unsigned long long delta; + unsigned long long val; + const char *comm; + int ret; + + if (!next_comm) { + prev_pid = get_field(event, "prev_pid"); + + next_comm = get_field(event, "next_comm"); + next_pid = get_field(event, "next_pid"); + } + + tep_read_number_field(prev_pid, record->data, &val); + + if (val) { + ret = stop_task(data->teval_tasks, val, &comm, record->ts, &delta); + if (ret > 0) + insert_task(data->teval_tasks, comm, val, delta, record->ts); + } + + tep_read_number_field(next_pid, record->data, &val); + + if (val) { + comm = record->data + next_comm->offset; + start_task(data->teval_tasks, val, comm, record->ts); + start_cpu(data->teval_cpus, record->cpu, record->ts); + return 0; + } + + ret = stop_cpu(data->teval_cpus, record->cpu, record->ts, &delta); + if (ret > 0) + insert_cpu(data->teval_cpus, record->cpu, delta, record->ts); + + return 0; +} + +static void print_microseconds(int idx, unsigned long long nsecs) +{ + unsigned long long usecs; + + usecs = nsecs / 1000; + if (!nsecs || usecs) + printf("%*lld", idx, usecs); + else + printf("%*d.%03lld", idx, 0, nsecs); +} + +static void print_stat(struct traceeval_stat *stat) +{ + unsigned long long average; + unsigned long long total; + unsigned long long cnt; + unsigned long long ts; + double stddev; + + printf("\tmax: "); + print_microseconds(12, traceeval_stat_max_timestamp(stat, &ts)); + printf(" timestamp: "); + print_microseconds(10, ts); + printf("\n\tmin: "); + print_microseconds(12, traceeval_stat_min_timestamp(stat, &ts)); + printf(" timestamp: "); + print_microseconds(10, ts); + printf("\n\ttotal: "); + total = traceeval_stat_total(stat); + print_microseconds(10, total); + cnt = traceeval_stat_count(stat); + printf("\n\tcount: %*lld\n", 10, cnt); + average = traceeval_stat_average(stat); + printf("\taverage: "); + print_microseconds(8, average); + stddev = traceeval_stat_stddev(stat); + printf("\n\tstddev: %*.3f\n", 13, stddev / 1000); +} + +static void display_cpus(struct traceeval *teval) +{ + struct traceeval_iterator *iter = traceeval_iterator_get(teval); + const struct traceeval_data *keys; + + printf("\n"); + + traceeval_iterator_sort(iter, cpu_types[0].name, 0, true); + + while (traceeval_iterator_next(iter, &keys) > 0) { + struct traceeval_stat *stat; + + stat = traceeval_iterator_stat(iter, delta_type[0].name); + + printf("CPU [%zd]:\n", keys[0].number); + print_stat(stat); + } + traceeval_iterator_put(iter); +} + +static void display_tasks(struct traceeval *teval) +{ + struct traceeval_iterator *iter = traceeval_iterator_get(teval); + const struct traceeval_data *keys; + + printf("\n"); + + traceeval_iterator_sort(iter, task_types[0].name, 0, true); + traceeval_iterator_sort(iter, task_types[1].name, 1, true); + + while (traceeval_iterator_next(iter, &keys) > 0) { + struct traceeval_stat *stat; + + stat = traceeval_iterator_stat(iter, delta_type[0].name); + + printf("Task %s [%zd]:\n", keys[0].cstring, keys[1].number); + print_stat(stat); + } + traceeval_iterator_put(iter); +}; + +int main (int argc, char **argv) +{ + struct tracecmd_input *handle; + struct data data; + + if (argc < 2) { + printf("Need to pass trace.dat file to this\n"); + exit(-1); + } + + handle = tracecmd_open(argv[1], TRACECMD_FL_LOAD_NO_PLUGINS); + + data.teval_tasks = traceeval_init(task_types, delta_type); + traceeval_delta_create(data.teval_tasks, task_delta_types, task_delta_val_types); + data.teval_cpus = traceeval_init(cpu_types, delta_type); + traceeval_delta_create(data.teval_cpus, cpu_delta_types, NULL); + + tracecmd_follow_event(handle, "sched", "sched_switch", switch_func, &data); + tracecmd_iterate_events(handle, NULL, 0, NULL, NULL); + + display_cpus(data.teval_cpus); + display_tasks(data.teval_tasks); + + traceeval_release(data.teval_cpus); + traceeval_release(data.teval_tasks); + + return 0; +} +-- + +FILES +----- +[verse] +-- +*traceval.h* + Header file to include in order to have access to the library APIs. +*-ltraceeval* + Linker switch to add when building a program that uses the library. +-- + +SEE ALSO +-------- +*libtraceeval*(3) + +AUTHOR +------ +[verse] +-- +*Steven Rostedt* <rostedt@xxxxxxxxxxx>, author of *libtraceeval*. +-- +REPORTING BUGS +-------------- +Report bugs to <linux-trace-devel@xxxxxxxxxxxxxxx> + +LICENSE +------- +libtraceeval is licensed under MIT. + diff --git a/Documentation/libtraceeval.txt b/Documentation/libtraceeval.txt index e65ebd270445..e856d1152594 100644 --- a/Documentation/libtraceeval.txt +++ b/Documentation/libtraceeval.txt @@ -76,6 +76,46 @@ Functions to manage statistics of values of a traceeval: unsigned long long *traceeval_stat_count*(struct traceeval_stat pass:[*]_stat_); unsigned long long *traceeval_stat_average*(struct traceeval_stat pass:[*]_stat_); double *traceeval_stat_stddev*(struct traceeval_stat pass:[*]_stat_); + +Handling delta times between events: + int *traceeval_delta_create*(struct traceeval pass:[*]_teval_, + struct traceeval_type pass:[*]_keys_, + struct traceeval_type pass:[*]_vals_); + int *traceeval_delta_create_size*(struct traceeval pass:[*]_teval_, + struct traceeval_type pass:[*]_keys_, + struct traceeval_type pass:[*]_vals_, + size_t _nr_keys_, size_t _nr_vals_); + + int *traceeval_delta_start*(struct traceeval pass:[*]_teval_, + const struct traceeval_data pass:[*]_keys_, + const struct traceeval_data pass:[*]_vals_, + unsigned long long _timestamp_); + int *traceeval_delta_start_size*(struct traceeval pass:[*]_teval_, + const struct traceeval_data pass:[*]_keys_, size_t _nr_keys_, + const struct traceeval_data pass:[*]_vals_, size_t _nr_vals_, + unsigned long long _timestamp_); + + int *traceeval_delta_stop*(struct traceeval pass:[*]_teval_, + const struct traceeval_data pass:[*]_keys_, + const struct traceeval_data pass:[**]_results_, + unsigned long long _timestamp_, + unsigned long long *_delta_, + unsigned long long *_start_timestamp_); + int *traceeval_delta_stop_size*(struct traceeval pass:[*]_teval_, + const struct traceeval_data pass:[*]_keys_, size_t _nr_keys_, + const struct traceeval_data pass:[**]_results_, + unsigned long long _timestamp_, + unsigned long long *_delta_, + unsigned long long *_start_timestamp_); + + int *traceeval_delta_continue*(struct traceeval pass:[*]_teval_, + const struct traceeval_data pass:[*]_keys_, + const struct traceeval_data pass:[*]_vals_, + unsigned long long _timestamp_); + int *traceeval_delta_continue_size*(struct traceeval pass:[*]_teval_, + const struct traceeval_data pass:[*]keys, size_t _nr_keys_, + const struct traceeval_data pass:[*]_vals_, size_t _nr_vals_, + unsigned long long _timestamp_); -- DESCRIPTION -- 2.42.0
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