Commit 0a892c1c authored by Ian Rogers's avatar Ian Rogers Committed by Arnaldo Carvalho de Melo
Browse files

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: default avatarStephane Eranian <eranian@google.com>
Signed-off-by: default avatarIan Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20200422173615.59436-1-irogers@google.com


[ split from a larger patch ]
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 5885a202

tools/perf/builtin-record.c

+14 −5
Original line number Diff line number Diff line
@@ -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;

		/*

		 * 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);

tools/perf/tests/attr/system-wide-dummy

0 → 100644
+50 −0
Original line number Diff line number Diff line 
# 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

tools/perf/tests/attr/test-record-C0

+10 −2
Original line number Diff line number Diff line
@@ -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]

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