From 7f8f56475d58511729429b2e52787606c4062ad0 Mon Sep 17 00:00:00 2001 From: Howard Chu Date: Wed, 30 Apr 2025 19:28:03 -0700 Subject: [PATCH] perf evsel: Assemble off-cpu samples Use the data in bpf-output samples, to assemble off-cpu samples. In evsel__is_offcpu_event(), check if sample_type is PERF_SAMPLE_RAW to support off-cpu sample data created by an older version of perf. Testing compatibility on off-cpu samples collected by perf before this patch series: See below, the sample_type still uses PERF_SAMPLE_CALLCHAIN $ perf script --header -i ./perf.data.ptn | grep "event : name = offcpu-time" # event : name = offcpu-time, , id = { 237917, 237918, 237919, 237920 }, type = 1 (software), size = 136, config = 0xa (PERF_COUNT_SW_BPF_OUTPUT), { sample_period, sample_freq } = 1, sample_type = IP|TID|TIME|CALLCHAIN|CPU|PERIOD|IDENTIFIER, read_format = ID|LOST, disabled = 1, freq = 1, sample_id_all = 1 The output is correct. $ perf script -i ./perf.data.ptn | grep offcpu-time gmain 2173 [000] 18446744069.414584: 100102015 offcpu-time: NetworkManager 901 [000] 18446744069.414584: 5603579 offcpu-time: Web Content 1183550 [000] 18446744069.414584: 46278 offcpu-time: gnome-control-c 2200559 [000] 18446744069.414584: 11998247014 offcpu-time: $ And after this patch series: $ perf script --header -i ./perf.data.off-cpu-v9 | grep "event : name = offcpu-time" # event : name = offcpu-time, , id = { 237959, 237960, 237961, 237962 }, type = 1 (software), size = 136, config = 0xa (PERF_COUNT_SW_BPF_OUTPUT), { sample_period, sample_freq } = 1, sample_type = IP|TID|TIME|CPU|PERIOD|RAW|IDENTIFIER, read_format = ID|LOST, disabled = 1, freq = 1, sample_id_all = 1 $ ./perf script -i ./perf.data.off-cpu-v9 | grep offcpu-time gnome-shell 1875 [001] 4789616.361225: 100097057 offcpu-time: gnome-shell 1875 [001] 4789616.461419: 100107463 offcpu-time: firefox 2206821 [002] 4789616.475690: 255257245 offcpu-time: $ Committer testing: The command to record those samples: root@number:~# perf record --off-cpu -a sleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 2.092 MB perf.data (1552 samples) ] root@number:~# Then, before this patch series, the sample_type for the "offcpu-time" event is: root@number:~# perf evlist -v | grep offcpu-time offcpu-time: type: 1 (PERF_TYPE_SOFTWARE), size: 136, config: 0xa (PERF_COUNT_SW_BPF_OUTPUT), { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CALLCHAIN|CPU|PERIOD|IDENTIFIER, read_format: ID|LOST, disabled: 1, freq: 1, sample_id_all: 1 root@number:~# And after it, after recording it again: root@number:~# perf record --off-cpu -a sleep 1 ; perf evlist -v | grep offcpu-time [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 2.151 MB perf.data (2843 samples) ] offcpu-time: type: 1 (PERF_TYPE_SOFTWARE), size: 136, config: 0xa (PERF_COUNT_SW_BPF_OUTPUT), { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CPU|PERIOD|IDENTIFIER, read_format: ID|LOST, disabled: 1, sample_id_all: 1 root@number:~# Suggested-by: Namhyung Kim Reviewed-by: Ian Rogers Signed-off-by: Howard Chu Tested-by: Arnaldo Carvalho de Melo Tested-by: Gautam Menghani Tested-by: Ian Rogers Acked-by: Namhyung Kim Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20241108204137.2444151-7-howardchu95@gmail.com Link: https://lore.kernel.org/r/20250501022809.449767-6-howardchu95@gmail.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/evsel.c | 35 ++++++++++++++++++++++++++++++++++- 1 file changed, 34 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index 2415e067b892..b60461e16804 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -1277,7 +1277,8 @@ static void evsel__set_default_freq_period(struct record_opts *opts, bool evsel__is_offcpu_event(struct evsel *evsel) { - return evsel__is_bpf_output(evsel) && evsel__name_is(evsel, OFFCPU_EVENT); + return evsel__is_bpf_output(evsel) && evsel__name_is(evsel, OFFCPU_EVENT) && + evsel->core.attr.sample_type & PERF_SAMPLE_RAW; } /* @@ -2923,6 +2924,35 @@ static inline bool evsel__has_branch_counters(const struct evsel *evsel) return false; } +static int __set_offcpu_sample(struct perf_sample *data) +{ + u64 *array = data->raw_data; + u32 max_size = data->raw_size, *p32; + const void *endp = (void *)array + max_size; + + if (array == NULL) + return -EFAULT; + + OVERFLOW_CHECK_u64(array); + p32 = (void *)array++; + data->pid = p32[0]; + data->tid = p32[1]; + + OVERFLOW_CHECK_u64(array); + data->period = *array++; + + OVERFLOW_CHECK_u64(array); + data->callchain = (struct ip_callchain *)array++; + OVERFLOW_CHECK(array, data->callchain->nr * sizeof(u64), max_size); + data->ip = data->callchain->ips[1]; + array += data->callchain->nr; + + OVERFLOW_CHECK_u64(array); + data->cgroup = *array; + + return 0; +} + int evsel__parse_sample(struct evsel *evsel, union perf_event *event, struct perf_sample *data) { @@ -3277,6 +3307,9 @@ int evsel__parse_sample(struct evsel *evsel, union perf_event *event, array = (void *)array + sz; } + if (evsel__is_offcpu_event(evsel)) + return __set_offcpu_sample(data); + return 0; } -- 2.51.0