Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | From | Namhyung Kim <> | Date | Mon, 22 Apr 2024 12:45:45 -0700 | Subject | Re: [RFC PATCH v7 3/6] perf stat: Fork and launch perf record when perf stat needs to get retire latency value for a metric. |
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On Tue, Apr 2, 2024 at 2:46 PM <weilin.wang@intel.com> wrote: > > From: Weilin Wang <weilin.wang@intel.com> > > When retire_latency value is used in a metric formula, perf stat would fork a > perf record process with "-e" and "-W" options. Perf record will collect > required retire_latency values in parallel while perf stat is collecting > counting values. > > At the point of time that perf stat stops counting, it would send sigterm signal > to perf record process and receiving sampling data back from perf record from a > pipe. Perf stat will then process the received data to get retire latency data > and calculate metric result. > > Another thread is required to synchronize between perf stat and perf record > when we pass data through pipe.
I feel like I'm repeating some of the precious review comments..
Still I think it's better to split these special case handling routines from the normal perf stat code.
> > Signed-off-by: Weilin Wang <weilin.wang@intel.com> > Reviewed-by: Ian Rogers <irogers@google.com> > --- > tools/perf/builtin-stat.c | 212 +++++++++++++++++++++++++++++++++- > tools/perf/util/metricgroup.h | 8 ++ > tools/perf/util/stat.h | 2 + > 3 files changed, 220 insertions(+), 2 deletions(-) > > diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c > index 4558b9d95441..2dcc1a12f7ef 100644 > --- a/tools/perf/builtin-stat.c > +++ b/tools/perf/builtin-stat.c > @@ -94,8 +94,13 @@ > #include <perf/evlist.h> > #include <internal/threadmap.h> > > +#include "util/sample.h" > +#include <sys/param.h> > +#include <subcmd/run-command.h> > + > #define DEFAULT_SEPARATOR " " > #define FREEZE_ON_SMI_PATH "devices/cpu/freeze_on_smi" > +#define PERF_DATA "-" > > static void print_counters(struct timespec *ts, int argc, const char **argv); > > @@ -163,6 +168,8 @@ static struct perf_stat_config stat_config = { > .ctl_fd_ack = -1, > .iostat_run = false, > .tpebs_events = LIST_HEAD_INIT(stat_config.tpebs_events), > + .tpebs_results = LIST_HEAD_INIT(stat_config.tpebs_results),
Can we combine these two lists? Why not move the result fields to tpebs_events?
> + .tpebs_pid = -1, > }; > > static bool cpus_map_matched(struct evsel *a, struct evsel *b) > @@ -684,15 +691,173 @@ static enum counter_recovery stat_handle_error(struct evsel *counter) > > if (child_pid != -1) > kill(child_pid, SIGTERM); > + if (stat_config.tpebs_pid != -1) > + kill(stat_config.tpebs_pid, SIGTERM); > return COUNTER_FATAL; > } > > -static int __run_perf_record(void) > +static int __run_perf_record(const char **record_argv) > { > + int i = 0; > + struct tpebs_event *e; > + > pr_debug("Prepare perf record for retire_latency\n"); > + > + record_argv[i++] = "perf"; > + record_argv[i++] = "record"; > + record_argv[i++] = "-W"; > + record_argv[i++] = "--synth=no"; > + > + if (stat_config.user_requested_cpu_list) { > + record_argv[i++] = "-C"; > + record_argv[i++] = stat_config.user_requested_cpu_list; > + } > + > + if (stat_config.system_wide) > + record_argv[i++] = "-a"; > + > + if (!stat_config.system_wide && !stat_config.user_requested_cpu_list) { > + pr_err("Require -a or -C option to run sampling.\n"); > + return -ECANCELED; > + } > + > + list_for_each_entry(e, &stat_config.tpebs_events, nd) { > + record_argv[i++] = "-e"; > + record_argv[i++] = e->name; > + } > + > + record_argv[i++] = "-o"; > + record_argv[i++] = PERF_DATA; > + > + return 0; > +} > + > +static void prepare_run_command(struct child_process *cmd, > + const char **argv) > +{ > + memset(cmd, 0, sizeof(*cmd)); > + cmd->argv = argv; > + cmd->out = -1; > +} > + > +static int prepare_perf_record(struct child_process *cmd) > +{ > + const char **record_argv; > + int ret; > + > + record_argv = calloc(10 + 2 * stat_config.tpebs_event_size, sizeof(char *)); > + if (!record_argv) > + return -1; > + > + ret = __run_perf_record(record_argv); > + if (ret) > + return ret;
free(record_argv) before return.
> + > + prepare_run_command(cmd, record_argv); > + return start_command(cmd); > +} > + > +struct perf_script { > + struct perf_tool tool; > + struct perf_session *session; > +}; > + > +static void tpebs_event_name__delete(struct tpebs_event *e) > +{ > + zfree(&e->name); > + zfree(&e->tpebs_name); > +} > + > +static void tpebs_event__delete(struct tpebs_event *e) > +{ > + tpebs_event_name__delete(e); > + free(e); > +} > + > +static void tpebs_retire_lat__delete(struct tpebs_retire_lat *r) > +{ > + tpebs_event_name__delete(&r->event); > + free(r); > +} > + > +static void tpebs_data__delete(void) > +{ > + struct tpebs_retire_lat *r, *rtmp; > + struct tpebs_event *e, *etmp; > + > + list_for_each_entry_safe(r, rtmp, &stat_config.tpebs_results, event.nd) { > + list_del_init(&r->event.nd); > + tpebs_retire_lat__delete(r); > + } > + list_for_each_entry_safe(e, etmp, &stat_config.tpebs_events, nd) { > + list_del_init(&e->nd); > + tpebs_event__delete(e); > + } > +} > + > +static int process_sample_event(struct perf_tool *tool __maybe_unused, > + union perf_event *event __maybe_unused, > + struct perf_sample *sample, > + struct evsel *evsel, > + struct machine *machine __maybe_unused) > +{ > + int ret = 0; > + const char *evname; > + struct tpebs_retire_lat *t; > + > + evname = evsel__name(evsel); > + > + /* > + * Need to handle per core results? We are assuming average retire > + * latency value will be used. Save the number of samples and the sum of > + * retire latency value for each event. > + */ > + list_for_each_entry(t, &stat_config.tpebs_results, event.nd) { > + if (!strcmp(evname, t->event.name)) { > + t->count += 1; > + t->sum += sample->retire_lat; > + break; > + } > + } > + > + return ret; > +} > + > +static int process_feature_event(struct perf_session *session, > + union perf_event *event) > +{ > + if (event->feat.feat_id < HEADER_LAST_FEATURE) > + return perf_event__process_feature(session, event); > return 0; > } > > +static void *__sample_reader(void *arg) > +{ > + struct child_process *cmd = arg; > + struct perf_session *session; > + struct perf_data data = { > + .mode = PERF_DATA_MODE_READ, > + .path = PERF_DATA, > + .file.fd = cmd->out, > + }; > + struct perf_script script = { > + .tool = { > + .sample = process_sample_event, > + .feature = process_feature_event, > + .attr = perf_event__process_attr, > + }, > + }; > + > + session = perf_session__new(&data, &script.tool); > + if (IS_ERR(session)) > + return NULL; > + script.session = session; > + perf_session__process_events(session); > + perf_session__delete(session); > + > + return NULL; > +}
Now we have weight[123] fields to show the average weight. Can we simply use it like below?
$ perf mem record -t load -o- timeout 1 perf test -w datasym | \ perf report -i- -q -F weight1 [ perf record: Woken up 3 times to write data ] [ perf record: Captured and wrote 0.614 MB - ] 92.2 <--- this
> + > static int __run_perf_stat(int argc, const char **argv, int run_idx) > { > int interval = stat_config.interval; > @@ -709,6 +874,8 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx) > struct affinity saved_affinity, *affinity = NULL; > int err; > bool second_pass = false; > + struct child_process cmd; > + pthread_t reader_thread; > > /* > * Prepare perf record for sampling event retire_latency before fork and > @@ -716,10 +883,35 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx) > */ > if (stat_config.tpebs_event_size > 0) { > int ret; > + struct tpebs_event *e; > + > + pr_debug("perf stat pid = %d\n", getpid()); > + list_for_each_entry(e, &stat_config.tpebs_events, nd) { > + struct tpebs_retire_lat *new = malloc(sizeof(struct tpebs_retire_lat)); > > - ret = __run_perf_record(); > + if (!new) > + return -1; > + new->event.name = strdup(e->name); > + if (!new->event.name) > + return -ENOMEM; > + new->event.tpebs_name = strdup(e->tpebs_name); > + if (!new->event.tpebs_name) > + return -ENOMEM; > + new->count = 0; > + new->sum = 0; > + list_add_tail(&new->event.nd, &stat_config.tpebs_results); > + } > + ret = prepare_perf_record(&cmd); > if (ret) > return ret; > + if (pthread_create(&reader_thread, NULL, __sample_reader, &cmd)) { > + kill(cmd.pid, SIGTERM); > + close(cmd.out); > + pr_err("Could not create thread to process sample data.\n"); > + return -1; > + } > + /* Wait for perf record initialization a little bit.*/ > + sleep(2);
This won't guarantee anything and just slows down the normal case. You'd better make the record process wait until the reader is ready.
Thanks, Namhyung
> } > > if (forks) { > @@ -927,6 +1119,17 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx) > > t1 = rdclock(); > > + if (stat_config.tpebs_event_size > 0) { > + int ret; > + > + kill(cmd.pid, SIGTERM); > + pthread_join(reader_thread, NULL); > + close(cmd.out); > + ret = finish_command(&cmd); > + if (ret != -ERR_RUN_COMMAND_WAITPID_SIGNAL) > + return ret; > + } > + > if (stat_config.walltime_run_table) > stat_config.walltime_run[run_idx] = t1 - t0; > > @@ -1034,6 +1237,9 @@ static void sig_atexit(void) > if (child_pid != -1) > kill(child_pid, SIGTERM); > > + if (stat_config.tpebs_pid != -1) > + kill(stat_config.tpebs_pid, SIGTERM); > + > sigprocmask(SIG_SETMASK, &oset, NULL); > > if (signr == -1) > @@ -2974,5 +3180,7 @@ int cmd_stat(int argc, const char **argv) > metricgroup__rblist_exit(&stat_config.metric_events); > evlist__close_control(stat_config.ctl_fd, stat_config.ctl_fd_ack, &stat_config.ctl_fd_close); > > + tpebs_data__delete(); > + > return status; > } > diff --git a/tools/perf/util/metricgroup.h b/tools/perf/util/metricgroup.h > index 7c24ed768ff3..ae788edef30f 100644 > --- a/tools/perf/util/metricgroup.h > +++ b/tools/perf/util/metricgroup.h > @@ -68,10 +68,18 @@ struct metric_expr { > > struct tpebs_event { > struct list_head nd; > + /* Event name */ > const char *name; > + /* Event name with the TPEBS modifier R */ > const char *tpebs_name; > }; > > +struct tpebs_retire_lat { > + struct tpebs_event event; > + size_t count; > + int sum; > +}; > + > struct metric_event *metricgroup__lookup(struct rblist *metric_events, > struct evsel *evsel, > bool create); > diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h > index b987960df3c5..0726bdc06681 100644 > --- a/tools/perf/util/stat.h > +++ b/tools/perf/util/stat.h > @@ -111,6 +111,8 @@ struct perf_stat_config { > struct rblist metric_events; > struct list_head tpebs_events; > size_t tpebs_event_size; > + struct list_head tpebs_results; > + pid_t tpebs_pid; > int ctl_fd; > int ctl_fd_ack; > bool ctl_fd_close; > -- > 2.43.0 >
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