From 0a892c1c947230f9373c9a3c94df1babe989861f Mon Sep 17 00:00:00 2001 From: Ian Rogers Date: Wed, 22 Apr 2020 10:36:15 -0700 Subject: [PATCH] perf record: Add dummy event during system wide synthesis During the processing of /proc during event synthesis new processes may start. Add a dummy event if /proc is to be processed, to capture mmaps for starting processes. This reuses the existing logic for initial-delay. v3 fixes the attr test of test-record-C0 v2 fixes the dummy event configuration and a branch stack issue. Suggested-by: Stephane Eranian Signed-off-by: Ian Rogers Cc: Alexander Shishkin Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Stephane Eranian Link: http://lore.kernel.org/lkml/20200422173615.59436-1-irogers@google.com [ split from a larger patch ] Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-record.c | 19 +++++++--- tools/perf/tests/attr/system-wide-dummy | 50 +++++++++++++++++++++++++ tools/perf/tests/attr/test-record-C0 | 12 +++++- 3 files changed, 74 insertions(+), 7 deletions(-) create mode 100644 tools/perf/tests/attr/system-wide-dummy diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index e4efdbf1a81e..4d4502b7fea0 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -825,19 +825,28 @@ static int record__open(struct record *rec) int rc = 0; /* - * For initial_delay we need to add a dummy event so that we can track - * PERF_RECORD_MMAP while we wait for the initial delay to enable the - * real events, the ones asked by the user. + * For initial_delay or system wide, we need to add a dummy event so + * that we can track PERF_RECORD_MMAP to cover the delay of waiting or + * event synthesis. */ - if (opts->initial_delay) { + if (opts->initial_delay || target__has_cpu(&opts->target)) { if (perf_evlist__add_dummy(evlist)) return -ENOMEM; + /* Disable tracking of mmaps on lead event. */ pos = evlist__first(evlist); pos->tracking = 0; + /* Set up dummy event. */ pos = evlist__last(evlist); pos->tracking = 1; - pos->core.attr.enable_on_exec = 1; + /* + * Enable the dummy event when the process is forked for + * initial_delay, immediately for system wide. + */ + if (opts->initial_delay) + pos->core.attr.enable_on_exec = 1; + else + pos->immediate = 1; } perf_evlist__config(evlist, opts, &callchain_param); diff --git a/tools/perf/tests/attr/system-wide-dummy b/tools/perf/tests/attr/system-wide-dummy new file mode 100644 index 000000000000..eba723cc0d38 --- /dev/null +++ b/tools/perf/tests/attr/system-wide-dummy @@ -0,0 +1,50 @@ +# Event added by system-wide or CPU perf-record to handle the race of +# processes starting while /proc is processed. +[event] +fd=1 +group_fd=-1 +cpu=* +pid=-1 +flags=8 +type=1 +size=120 +config=9 +sample_period=4000 +sample_type=455 +read_format=4 +# Event will be enabled right away. +disabled=0 +inherit=1 +pinned=0 +exclusive=0 +exclude_user=0 +exclude_kernel=0 +exclude_hv=0 +exclude_idle=0 +mmap=1 +comm=1 +freq=1 +inherit_stat=0 +enable_on_exec=0 +task=1 +watermark=0 +precise_ip=0 +mmap_data=0 +sample_id_all=1 +exclude_host=0 +exclude_guest=0 +exclude_callchain_kernel=0 +exclude_callchain_user=0 +mmap2=1 +comm_exec=1 +context_switch=0 +write_backward=0 +namespaces=0 +use_clockid=0 +wakeup_events=0 +bp_type=0 +config1=0 +config2=0 +branch_sample_type=0 +sample_regs_user=0 +sample_stack_user=0 diff --git a/tools/perf/tests/attr/test-record-C0 b/tools/perf/tests/attr/test-record-C0 index 93818054ae20..317730b906dd 100644 --- a/tools/perf/tests/attr/test-record-C0 +++ b/tools/perf/tests/attr/test-record-C0 @@ -9,6 +9,14 @@ cpu=0 # no enable on exec for CPU attached enable_on_exec=0 -# PERF_SAMPLE_IP | PERF_SAMPLE_TID PERF_SAMPLE_TIME | # PERF_SAMPLE_PERIOD +# PERF_SAMPLE_IP | PERF_SAMPLE_TID | PERF_SAMPLE_TIME | +# PERF_SAMPLE_ID | PERF_SAMPLE_PERIOD # + PERF_SAMPLE_CPU added by -C 0 -sample_type=391 +sample_type=455 + +# Dummy event handles mmaps, comm and task. +mmap=0 +comm=0 +task=0 + +[event:system-wide-dummy]