diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt index 7d18694e592af26a29fdeabf032deb7a17b1091d..5bf3d7ae466008d2027287b0fabcc880a21e5dc3 100644 --- a/tools/perf/Documentation/perf-stat.txt +++ b/tools/perf/Documentation/perf-stat.txt @@ -363,6 +363,11 @@ if the workload is actually bound by the CPU and not by something else. For best results it is usually a good idea to use it with interval mode like -I 1000, as the bottleneck of workloads can change often. +This enables --metric-only, unless overridden with --no-metric-only. + +The following restrictions only apply to older Intel CPUs and Atom, +on newer CPUs (IceLake and later) TopDown can be collected for any thread: + The top down metrics are collected per core instead of per CPU thread. Per core mode is automatically enabled and -a (global monitoring) is needed, requiring root rights or @@ -374,8 +379,6 @@ echo 0 > /proc/sys/kernel/nmi_watchdog for best results. Otherwise the bottlenecks may be inconsistent on workload with changing phases. -This enables --metric-only, unless overridden with --no-metric-only. - To interpret the results it is usually needed to know on which CPUs the workload runs on. If needed the CPUs can be forced using taskset. diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c index a39bb28b44f93484f8d83cda3b946e5a0fccc031..17fbbd03e15484e434a39eb3cf1c9b03af2e08a7 100644 --- a/tools/perf/builtin-stat.c +++ b/tools/perf/builtin-stat.c @@ -128,6 +128,15 @@ static const char * topdown_attrs[] = { NULL, }; +static const char *topdown_metric_attrs[] = { + "slots", + "topdown-retiring", + "topdown-bad-spec", + "topdown-fe-bound", + "topdown-be-bound", + NULL, +}; + static const char *smi_cost_attrs = { "{" "msr/aperf/," @@ -1677,6 +1686,24 @@ static int add_default_attributes(void) char *str = NULL; bool warn = false; + if (!force_metric_only) + stat_config.metric_only = true; + + if (topdown_filter_events(topdown_metric_attrs, &str, 1) < 0) { + pr_err("Out of memory\n"); + return -1; + } + if (topdown_metric_attrs[0] && str) { + if (!stat_config.interval && !stat_config.metric_only) { + fprintf(stat_config.output, + "Topdown accuracy may decrease when measuring long periods.\n" + "Please print the result regularly, e.g. -I1000\n"); + } + goto setup_metrics; + } + + zfree(&str); + if (stat_config.aggr_mode != AGGR_GLOBAL && stat_config.aggr_mode != AGGR_CORE) { pr_err("top down event configuration requires --per-core mode\n"); @@ -1688,8 +1715,6 @@ static int add_default_attributes(void) return -1; } - if (!force_metric_only) - stat_config.metric_only = true; if (topdown_filter_events(topdown_attrs, &str, arch_topdown_check_group(&warn)) < 0) { pr_err("Out of memory\n"); @@ -1698,6 +1723,7 @@ static int add_default_attributes(void) if (topdown_attrs[0] && str) { if (warn) arch_topdown_group_warn(); +setup_metrics: err = parse_events(evsel_list, str, &errinfo); if (err) { fprintf(stderr, diff --git a/tools/perf/util/stat-shadow.c b/tools/perf/util/stat-shadow.c index 924b54d15d5406b98d1236b57a8db0b90d46545d..901265127e3698126bc9f395058ee4f12fd05419 100644 --- a/tools/perf/util/stat-shadow.c +++ b/tools/perf/util/stat-shadow.c @@ -241,6 +241,18 @@ void perf_stat__update_shadow_stats(struct evsel *counter, u64 count, else if (perf_stat_evsel__is(counter, TOPDOWN_RECOVERY_BUBBLES)) update_runtime_stat(st, STAT_TOPDOWN_RECOVERY_BUBBLES, ctx, cpu, count); + else if (perf_stat_evsel__is(counter, TOPDOWN_RETIRING)) + update_runtime_stat(st, STAT_TOPDOWN_RETIRING, + ctx, cpu, count); + else if (perf_stat_evsel__is(counter, TOPDOWN_BAD_SPEC)) + update_runtime_stat(st, STAT_TOPDOWN_BAD_SPEC, + ctx, cpu, count); + else if (perf_stat_evsel__is(counter, TOPDOWN_FE_BOUND)) + update_runtime_stat(st, STAT_TOPDOWN_FE_BOUND, + ctx, cpu, count); + else if (perf_stat_evsel__is(counter, TOPDOWN_BE_BOUND)) + update_runtime_stat(st, STAT_TOPDOWN_BE_BOUND, + ctx, cpu, count); else if (evsel__match(counter, HARDWARE, HW_STALLED_CYCLES_FRONTEND)) update_runtime_stat(st, STAT_STALLED_CYCLES_FRONT, ctx, cpu, count); @@ -705,6 +717,47 @@ static double td_be_bound(int ctx, int cpu, struct runtime_stat *st) return sanitize_val(1.0 - sum); } +/* + * Kernel reports metrics multiplied with slots. To get back + * the ratios we need to recreate the sum. + */ + +static double td_metric_ratio(int ctx, int cpu, + enum stat_type type, + struct runtime_stat *stat) +{ + double sum = runtime_stat_avg(stat, STAT_TOPDOWN_RETIRING, ctx, cpu) + + runtime_stat_avg(stat, STAT_TOPDOWN_FE_BOUND, ctx, cpu) + + runtime_stat_avg(stat, STAT_TOPDOWN_BE_BOUND, ctx, cpu) + + runtime_stat_avg(stat, STAT_TOPDOWN_BAD_SPEC, ctx, cpu); + double d = runtime_stat_avg(stat, type, ctx, cpu); + + if (sum) + return d / sum; + return 0; +} + +/* + * ... but only if most of the values are actually available. + * We allow two missing. + */ + +static bool full_td(int ctx, int cpu, + struct runtime_stat *stat) +{ + int c = 0; + + if (runtime_stat_avg(stat, STAT_TOPDOWN_RETIRING, ctx, cpu) > 0) + c++; + if (runtime_stat_avg(stat, STAT_TOPDOWN_BE_BOUND, ctx, cpu) > 0) + c++; + if (runtime_stat_avg(stat, STAT_TOPDOWN_FE_BOUND, ctx, cpu) > 0) + c++; + if (runtime_stat_avg(stat, STAT_TOPDOWN_BAD_SPEC, ctx, cpu) > 0) + c++; + return c >= 2; +} + static void print_smi_cost(struct perf_stat_config *config, int cpu, struct evsel *evsel, struct perf_stat_output_ctx *out, @@ -1073,6 +1126,42 @@ void perf_stat__print_shadow_stats(struct perf_stat_config *config, be_bound * 100.); else print_metric(config, ctxp, NULL, NULL, name, 0); + } else if (perf_stat_evsel__is(evsel, TOPDOWN_RETIRING) && + full_td(ctx, cpu, st)) { + double retiring = td_metric_ratio(ctx, cpu, + STAT_TOPDOWN_RETIRING, st); + + if (retiring > 0.7) + color = PERF_COLOR_GREEN; + print_metric(config, ctxp, color, "%8.1f%%", "retiring", + retiring * 100.); + } else if (perf_stat_evsel__is(evsel, TOPDOWN_FE_BOUND) && + full_td(ctx, cpu, st)) { + double fe_bound = td_metric_ratio(ctx, cpu, + STAT_TOPDOWN_FE_BOUND, st); + + if (fe_bound > 0.2) + color = PERF_COLOR_RED; + print_metric(config, ctxp, color, "%8.1f%%", "frontend bound", + fe_bound * 100.); + } else if (perf_stat_evsel__is(evsel, TOPDOWN_BE_BOUND) && + full_td(ctx, cpu, st)) { + double be_bound = td_metric_ratio(ctx, cpu, + STAT_TOPDOWN_BE_BOUND, st); + + if (be_bound > 0.2) + color = PERF_COLOR_RED; + print_metric(config, ctxp, color, "%8.1f%%", "backend bound", + be_bound * 100.); + } else if (perf_stat_evsel__is(evsel, TOPDOWN_BAD_SPEC) && + full_td(ctx, cpu, st)) { + double bad_spec = td_metric_ratio(ctx, cpu, + STAT_TOPDOWN_BAD_SPEC, st); + + if (bad_spec > 0.1) + color = PERF_COLOR_RED; + print_metric(config, ctxp, color, "%8.1f%%", "bad speculation", + bad_spec * 100.); } else if (evsel->metric_expr) { generic_metric(config, evsel->metric_expr, evsel->metric_events, NULL, evsel->name, evsel->metric_name, NULL, 1, cpu, out, st); diff --git a/tools/perf/util/stat.c b/tools/perf/util/stat.c index cdb154381a87361de6a229c040217b350314c28d..bd0decd6d7535ed1c034863df738ac4f48904512 100644 --- a/tools/perf/util/stat.c +++ b/tools/perf/util/stat.c @@ -95,6 +95,10 @@ static const char *id_str[PERF_STAT_EVSEL_ID__MAX] = { ID(TOPDOWN_SLOTS_RETIRED, topdown-slots-retired), ID(TOPDOWN_FETCH_BUBBLES, topdown-fetch-bubbles), ID(TOPDOWN_RECOVERY_BUBBLES, topdown-recovery-bubbles), + ID(TOPDOWN_RETIRING, topdown-retiring), + ID(TOPDOWN_BAD_SPEC, topdown-bad-spec), + ID(TOPDOWN_FE_BOUND, topdown-fe-bound), + ID(TOPDOWN_BE_BOUND, topdown-be-bound), ID(SMI_NUM, msr/smi/), ID(APERF, msr/aperf/), }; diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h index 9911fc6adbfdd7e843be3212f051cc984545b790..f36c8c92efa0cd1d9359b25be3167c5bd33ebdeb 100644 --- a/tools/perf/util/stat.h +++ b/tools/perf/util/stat.h @@ -28,6 +28,10 @@ enum perf_stat_evsel_id { PERF_STAT_EVSEL_ID__TOPDOWN_SLOTS_RETIRED, PERF_STAT_EVSEL_ID__TOPDOWN_FETCH_BUBBLES, PERF_STAT_EVSEL_ID__TOPDOWN_RECOVERY_BUBBLES, + PERF_STAT_EVSEL_ID__TOPDOWN_RETIRING, + PERF_STAT_EVSEL_ID__TOPDOWN_BAD_SPEC, + PERF_STAT_EVSEL_ID__TOPDOWN_FE_BOUND, + PERF_STAT_EVSEL_ID__TOPDOWN_BE_BOUND, PERF_STAT_EVSEL_ID__SMI_NUM, PERF_STAT_EVSEL_ID__APERF, PERF_STAT_EVSEL_ID__MAX, @@ -82,6 +86,10 @@ enum stat_type { STAT_TOPDOWN_SLOTS_RETIRED, STAT_TOPDOWN_FETCH_BUBBLES, STAT_TOPDOWN_RECOVERY_BUBBLES, + STAT_TOPDOWN_RETIRING, + STAT_TOPDOWN_BAD_SPEC, + STAT_TOPDOWN_FE_BOUND, + STAT_TOPDOWN_BE_BOUND, STAT_SMI_NUM, STAT_APERF, STAT_MAX