From 3b0a18c1aa6cbfa7b0dd513b6be9893ef6e6ac30 Mon Sep 17 00:00:00 2001 From: Ian Rogers Date: Fri, 11 Sep 2020 19:56:54 -0700 Subject: [PATCH] perf record: Don't clear event's period if set by a term If events in a group explicitly set a frequency or period with leader sampling, don't disable the samples on those events. Prior to 5.8: perf record -e '{cycles/period=12345000/,instructions/period=6789000/}:S' would clear the attributes then apply the config terms. In commit 5f34278867b7 leader sampling configuration was moved to after applying the config terms, in the example, making the instructions' event have its period cleared. This change makes it so that sampling is only disabled if configuration terms aren't present. Committer testing: Before: # perf record -e '{cycles/period=1/,instructions/period=2/}:S' sleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.051 MB perf.data (6 samples) ] # # perf evlist -v cycles/period=1/: size: 120, { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|READ|ID, read_format: ID|GROUP, disabled: 1, mmap: 1, comm: 1, enable_on_exec: 1, task: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1, ksymbol: 1, bpf_event: 1 instructions/period=2/: size: 120, config: 0x1, sample_type: IP|TID|TIME|READ|ID, read_format: ID|GROUP, sample_id_all: 1, exclude_guest: 1 # After: # perf record -e '{cycles/period=1/,instructions/period=2/}:S' sleep 0.0001 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.052 MB perf.data (4 samples) ] # perf evlist -v cycles/period=1/: size: 120, { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|READ|ID, read_format: ID|GROUP, disabled: 1, mmap: 1, comm: 1, enable_on_exec: 1, task: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1, ksymbol: 1, bpf_event: 1 instructions/period=2/: size: 120, config: 0x1, { sample_period, sample_freq }: 2, sample_type: IP|TID|TIME|READ|ID, read_format: ID|GROUP, sample_id_all: 1, exclude_guest: 1 # Fixes: 5f34278867b7 ("perf evlist: Move leader-sampling configuration") Signed-off-by: Ian Rogers Acked-by: Adrian Hunter Acked-by: Jiri Olsa Tested-by: Arnaldo Carvalho de Melo Cc: Alexander Shishkin Cc: Alexei Starovoitov Cc: Andi Kleen Cc: Andrii Nakryiko Cc: Athira Jajeev Cc: Daniel Borkmann Cc: John Fastabend Cc: KP Singh Cc: Mark Rutland Cc: Martin KaFai Lau Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Song Liu Cc: Stephane Eranian Cc: Yonghong Song Link: http://lore.kernel.org/lkml/20200912025655.1337192-4-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/record.c | 34 ++++++++++++++++++++++++++-------- 1 file changed, 26 insertions(+), 8 deletions(-) diff --git a/tools/perf/util/record.c b/tools/perf/util/record.c index a4cc115..ea9aa1d 100644 --- a/tools/perf/util/record.c +++ b/tools/perf/util/record.c @@ -2,6 +2,7 @@ #include "debug.h" #include "evlist.h" #include "evsel.h" +#include "evsel_config.h" #include "parse-events.h" #include #include @@ -33,11 +34,24 @@ static struct evsel *evsel__read_sampler(struct evsel *evsel, struct evlist *evl return leader; } +static u64 evsel__config_term_mask(struct evsel *evsel) +{ + struct evsel_config_term *term; + struct list_head *config_terms = &evsel->config_terms; + u64 term_types = 0; + + list_for_each_entry(term, config_terms, list) { + term_types |= 1 << term->type; + } + return term_types; +} + static void evsel__config_leader_sampling(struct evsel *evsel, struct evlist *evlist) { struct perf_event_attr *attr = &evsel->core.attr; struct evsel *leader = evsel->leader; struct evsel *read_sampler; + u64 term_types, freq_mask; if (!leader->sample_read) return; @@ -47,16 +61,20 @@ static void evsel__config_leader_sampling(struct evsel *evsel, struct evlist *ev if (evsel == read_sampler) return; + term_types = evsel__config_term_mask(evsel); /* - * Disable sampling for all group members other than the leader in - * case the leader 'leads' the sampling, except when the leader is an - * AUX area event, in which case the 2nd event in the group is the one - * that 'leads' the sampling. + * Disable sampling for all group members except those with explicit + * config terms or the leader. In the case of an AUX area event, the 2nd + * event in the group is the one that 'leads' the sampling. */ - attr->freq = 0; - attr->sample_freq = 0; - attr->sample_period = 0; - attr->write_backward = 0; + freq_mask = (1 << EVSEL__CONFIG_TERM_FREQ) | (1 << EVSEL__CONFIG_TERM_PERIOD); + if ((term_types & freq_mask) == 0) { + attr->freq = 0; + attr->sample_freq = 0; + attr->sample_period = 0; + } + if ((term_types & (1 << EVSEL__CONFIG_TERM_OVERWRITE)) == 0) + attr->write_backward = 0; /* * We don't get a sample for slave events, we make them when delivering -- 2.7.4