From eb2eac0c7b6180332ced94d2979f3d3c7d22aaff Mon Sep 17 00:00:00 2001 From: Ian Rogers Date: Mon, 20 Nov 2023 16:04:20 -0800 Subject: [PATCH] perf evsel: Fallback to "task-clock" when not system wide When the "cycles" event isn't available evsel will fallback to the "cpu-clock" software event. "task-clock" is similar to "cpu-clock" but only runs when the process is running. Falling back to "cpu-clock" when not system wide leads to confusion, by falling back to "task-clock" it is hoped the confusion is less. Pass the target to determine if "task-clock" is more appropriate. Update a nearby comment and debug string for the change. Signed-off-by: Ian Rogers Tested-by: Athira Rajeev Acked-by: Namhyung Kim Cc: Adrian Hunter Cc: Ajay Kaher Cc: Alexander Shishkin Cc: Alexey Makhalov Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Leo Yan Cc: Mark Rutland Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Sandipan Das Cc: Yang Jihong Link: https://lore.kernel.org/r/20231121000420.368075-1-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-record.c | 2 +- tools/perf/builtin-stat.c | 2 +- tools/perf/builtin-top.c | 2 +- tools/perf/util/evsel.c | 18 ++++++++++-------- tools/perf/util/evsel.h | 3 ++- 5 files changed, 15 insertions(+), 12 deletions(-) diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index 9b4f3805ca92..db814eadc16b 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -1360,7 +1360,7 @@ static int record__open(struct record *rec) evlist__for_each_entry(evlist, pos) { try_again: if (evsel__open(pos, pos->core.cpus, pos->core.threads) < 0) { - if (evsel__fallback(pos, errno, msg, sizeof(msg))) { + if (evsel__fallback(pos, &opts->target, errno, msg, sizeof(msg))) { if (verbose > 0) ui__warning("%s\n", msg); goto try_again; diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c index a3af805a1d57..d8e5d6f7a87a 100644 --- a/tools/perf/builtin-stat.c +++ b/tools/perf/builtin-stat.c @@ -653,7 +653,7 @@ static enum counter_recovery stat_handle_error(struct evsel *counter) if ((evsel__leader(counter) != counter) || !(counter->core.leader->nr_members > 1)) return COUNTER_SKIP; - } else if (evsel__fallback(counter, errno, msg, sizeof(msg))) { + } else if (evsel__fallback(counter, &target, errno, msg, sizeof(msg))) { if (verbose > 0) ui__warning("%s\n", msg); return COUNTER_RETRY; diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c index ea8c7eca5eee..1e42bd1c7d5a 100644 --- a/tools/perf/builtin-top.c +++ b/tools/perf/builtin-top.c @@ -1044,7 +1044,7 @@ try_again: perf_top_overwrite_fallback(top, counter)) goto try_again; - if (evsel__fallback(counter, errno, msg, sizeof(msg))) { + if (evsel__fallback(counter, &opts->target, errno, msg, sizeof(msg))) { if (verbose > 0) ui__warning("%s\n", msg); goto try_again; diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index a5da74e3a517..532f34d9fcb5 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -2853,7 +2853,8 @@ u64 evsel__intval_common(struct evsel *evsel, struct perf_sample *sample, const #endif -bool evsel__fallback(struct evsel *evsel, int err, char *msg, size_t msgsize) +bool evsel__fallback(struct evsel *evsel, struct target *target, int err, + char *msg, size_t msgsize) { int paranoid; @@ -2861,18 +2862,19 @@ bool evsel__fallback(struct evsel *evsel, int err, char *msg, size_t msgsize) evsel->core.attr.type == PERF_TYPE_HARDWARE && evsel->core.attr.config == PERF_COUNT_HW_CPU_CYCLES) { /* - * If it's cycles then fall back to hrtimer based - * cpu-clock-tick sw counter, which is always available even if - * no PMU support. + * If it's cycles then fall back to hrtimer based cpu-clock sw + * counter, which is always available even if no PMU support. * * PPC returns ENXIO until 2.6.37 (behavior changed with commit * b0a873e). */ - scnprintf(msg, msgsize, "%s", -"The cycles event is not supported, trying to fall back to cpu-clock-ticks"); - evsel->core.attr.type = PERF_TYPE_SOFTWARE; - evsel->core.attr.config = PERF_COUNT_SW_CPU_CLOCK; + evsel->core.attr.config = target__has_cpu(target) + ? PERF_COUNT_SW_CPU_CLOCK + : PERF_COUNT_SW_TASK_CLOCK; + scnprintf(msg, msgsize, + "The cycles event is not supported, trying to fall back to %s", + target__has_cpu(target) ? "cpu-clock" : "task-clock"); zfree(&evsel->name); return true; diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h index f19ac9f027ef..efbb6e848287 100644 --- a/tools/perf/util/evsel.h +++ b/tools/perf/util/evsel.h @@ -460,7 +460,8 @@ static inline bool evsel__is_clock(const struct evsel *evsel) evsel__match(evsel, SOFTWARE, SW_TASK_CLOCK); } -bool evsel__fallback(struct evsel *evsel, int err, char *msg, size_t msgsize); +bool evsel__fallback(struct evsel *evsel, struct target *target, int err, + char *msg, size_t msgsize); int evsel__open_strerror(struct evsel *evsel, struct target *target, int err, char *msg, size_t size);