From b009b51eeac7a23e578641e96cfa08ab05cf6777 Mon Sep 17 00:00:00 2001 From: Ian Rogers Date: Mon, 14 Apr 2025 10:41:22 -0700 Subject: [PATCH] perf intel-tpebs: Separate evsel__tpebs_prepare() out of evsel__tpebs_open() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Separate the creation of the tpebs_retire_lat result out of the opening step. This is in preparation for adding a prepare operation for evlists. Reviewed-by: Kan Liang Signed-off-by: Ian Rogers Tested-by: Weilin Wang Acked-by: Namhyung Kim Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Alexandre Torgue Cc: Andreas Färber Cc: Caleb Biggers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Manivannan Sadhasivam Cc: Mark Rutland Cc: Maxime Coquelin Cc: Perry Taylor Cc: Peter Zijlstra Cc: Thomas Falcon Link: https://lore.kernel.org/r/20250414174134.3095492-5-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/intel-tpebs.c | 133 ++++++++++++++++++++++------------ 1 file changed, 86 insertions(+), 47 deletions(-) diff --git a/tools/perf/util/intel-tpebs.c b/tools/perf/util/intel-tpebs.c index 566e0ddcad884..2186818b2c9bc 100644 --- a/tools/perf/util/intel-tpebs.c +++ b/tools/perf/util/intel-tpebs.c @@ -37,7 +37,7 @@ static struct child_process tpebs_cmd; struct tpebs_retire_lat { struct list_head nd; /* Event name */ - const char *name; + char *name; /* Event name with the TPEBS modifier R */ const char *tpebs_name; /* Count of retire_latency values found in sample data */ @@ -190,6 +190,82 @@ static int tpebs_stop(void) return ret; } +static char *evsel__tpebs_name(struct evsel *evsel) +{ + char *name, *modifier; + + name = strdup(evsel->name); + if (!name) + return NULL; + + modifier = strrchr(name, 'R'); + if (!modifier) { + pr_err("Tpebs event missing modifier '%s'\n", name); + free(name); + return NULL; + } + + *modifier = 'p'; + return name; +} + +static struct tpebs_retire_lat *tpebs_retire_lat__new(struct evsel *evsel) +{ + struct tpebs_retire_lat *result = zalloc(sizeof(*result)); + + if (!result) + return NULL; + + result->tpebs_name = evsel->name; + result->name = evsel__tpebs_name(evsel); + if (!result->name) { + free(result); + return NULL; + } + list_add_tail(&result->nd, &tpebs_results); + tpebs_event_size++; + return result; +} + +/** + * evsel__tpebs_prepare - create tpebs data structures ready for opening. + * @evsel: retire_latency evsel, all evsels on its list will be prepared. + */ +static int evsel__tpebs_prepare(struct evsel *evsel) +{ + struct evsel *pos; + struct tpebs_retire_lat *tpebs_event; + + list_for_each_entry(tpebs_event, &tpebs_results, nd) { + if (!strcmp(tpebs_event->tpebs_name, evsel->name)) { + /* + * evsel, or an identically named one, was already + * prepared. + */ + return 0; + } + } + tpebs_event = tpebs_retire_lat__new(evsel); + if (!tpebs_event) + return -ENOMEM; + + /* + * Eagerly prepare all other evsels on the list to try to ensure that by + * open they are all known. + */ + evlist__for_each_entry(evsel->evlist, pos) { + int ret; + + if (pos == evsel || !pos->retire_lat) + continue; + + ret = evsel__tpebs_prepare(pos); + if (ret) + return ret; + } + return 0; +} + /** * evsel__tpebs_open - starts tpebs execution. * @evsel: retire_latency evsel, all evsels on its list will be selected. Each @@ -197,10 +273,7 @@ static int tpebs_stop(void) */ int evsel__tpebs_open(struct evsel *evsel) { - int ret = 0; - struct evsel *pos; - struct evlist *evsel_list = evsel->evlist; - char cpumap_buf[50]; + int ret; /* * We should only run tpebs_start when tpebs_recording is enabled. @@ -209,49 +282,13 @@ int evsel__tpebs_open(struct evsel *evsel) if (tpebs_cmd.pid != 0 || !tpebs_recording) return 0; - cpu_map__snprint(evsel_list->core.user_requested_cpus, cpumap_buf, sizeof(cpumap_buf)); - /* - * Prepare perf record for sampling event retire_latency before fork and - * prepare workload - */ - evlist__for_each_entry(evsel_list, pos) { - int i; - char *name; - struct tpebs_retire_lat *new; - - if (!pos->retire_lat) - continue; - - pr_debug("tpebs: Retire_latency of event %s is required\n", pos->name); - for (i = strlen(pos->name) - 1; i > 0; i--) { - if (pos->name[i] == 'R') - break; - } - if (i <= 0 || pos->name[i] != 'R') { - ret = -1; - goto err; - } - - name = strdup(pos->name); - if (!name) { - ret = -ENOMEM; - goto err; - } - name[i] = 'p'; - - new = zalloc(sizeof(*new)); - if (!new) { - ret = -1; - zfree(&name); - goto err; - } - new->name = name; - new->tpebs_name = pos->name; - list_add_tail(&new->nd, &tpebs_results); - tpebs_event_size += 1; - } + ret = evsel__tpebs_prepare(evsel); + if (ret) + return ret; if (tpebs_event_size > 0) { + struct evlist *evsel_list = evsel->evlist; + char cpumap_buf[50]; struct pollfd pollfd = { .events = POLLIN, }; int control_fd[2], ack_fd[2], len; char ack_buf[8]; @@ -268,6 +305,9 @@ int evsel__tpebs_open(struct evsel *evsel) goto out; } + cpu_map__snprint(evsel_list->core.user_requested_cpus, cpumap_buf, + sizeof(cpumap_buf)); + ret = start_perf_record(control_fd, ack_fd, cpumap_buf); if (ret) goto out; @@ -321,7 +361,6 @@ out: close(ack_fd[0]); close(ack_fd[1]); } -err: if (ret) tpebs_delete(); return ret; -- 2.39.5