Commit 30b331d2 authored by Namhyung Kim's avatar Namhyung Kim Committed by Arnaldo Carvalho de Melo
Browse files

perf lock: Allow concurrent record and report 



To support live monitoring of kernel lock contention without BPF,
it should support something like below:

  # perf lock record -a -o- sleep 1 | perf lock contention -i-
   contended   total wait     max wait     avg wait         type   caller

           2     10.27 us      6.17 us      5.13 us     spinlock   load_balance+0xc03
           1      5.29 us      5.29 us      5.29 us     rwlock:W   ep_scan_ready_list+0x54
           1      4.12 us      4.12 us      4.12 us     spinlock   smpboot_thread_fn+0x116
           1      3.28 us      3.28 us      3.28 us        mutex   pipe_read+0x50

To do that, it needs to handle HEAD_ATTR, HEADER_EVENT_UPDATE and
HEADER_TRACING_DATA which are generated only for the pipe mode.
And setting event handler also should be delayed until it gets the
event information.

Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
Acked-by: default avatarIan Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20221104051440.220989-1-namhyung@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 6ac73820

tools/perf/builtin-lock.c

+46 −22
Original line number Diff line number Diff line
@@ -1390,6 +1390,34 @@ static int dump_info(void) 
	return rc;

}



static const struct evsel_str_handler lock_tracepoints[] = {

	{ "lock:lock_acquire",	 evsel__process_lock_acquire,   }, /* CONFIG_LOCKDEP */

	{ "lock:lock_acquired",	 evsel__process_lock_acquired,  }, /* CONFIG_LOCKDEP, CONFIG_LOCK_STAT */

	{ "lock:lock_contended", evsel__process_lock_contended, }, /* CONFIG_LOCKDEP, CONFIG_LOCK_STAT */

	{ "lock:lock_release",	 evsel__process_lock_release,   }, /* CONFIG_LOCKDEP */

};



static const struct evsel_str_handler contention_tracepoints[] = {

	{ "lock:contention_begin", evsel__process_contention_begin, },

	{ "lock:contention_end",   evsel__process_contention_end,   },

};



static int process_event_update(struct perf_tool *tool,

				union perf_event *event,

				struct evlist **pevlist)

{

	int ret;



	ret = perf_event__process_event_update(tool, event, pevlist);

	if (ret < 0)

		return ret;



	/* this can return -EEXIST since we call it for each evsel */

	perf_session__set_tracepoints_handlers(session, lock_tracepoints);

	perf_session__set_tracepoints_handlers(session, contention_tracepoints);

	return 0;

}



typedef int (*tracepoint_handler)(struct evsel *evsel,

				  struct perf_sample *sample);
@@ -1545,28 +1573,19 @@ static void print_contention_result(struct lock_contention *con) 
	print_bad_events(bad, total);

}



static const struct evsel_str_handler lock_tracepoints[] = {

	{ "lock:lock_acquire",	 evsel__process_lock_acquire,   }, /* CONFIG_LOCKDEP */

	{ "lock:lock_acquired",	 evsel__process_lock_acquired,  }, /* CONFIG_LOCKDEP, CONFIG_LOCK_STAT */

	{ "lock:lock_contended", evsel__process_lock_contended, }, /* CONFIG_LOCKDEP, CONFIG_LOCK_STAT */

	{ "lock:lock_release",	 evsel__process_lock_release,   }, /* CONFIG_LOCKDEP */

};



static const struct evsel_str_handler contention_tracepoints[] = {

	{ "lock:contention_begin", evsel__process_contention_begin, },

	{ "lock:contention_end",   evsel__process_contention_end,   },

};



static bool force;



static int __cmd_report(bool display_info)

{

	int err = -EINVAL;

	struct perf_tool eops = {

		.attr		 = perf_event__process_attr,

		.event_update	 = process_event_update,

		.sample		 = process_sample_event,

		.comm		 = perf_event__process_comm,

		.mmap		 = perf_event__process_mmap,

		.namespaces	 = perf_event__process_namespaces,

		.tracing_data	 = perf_event__process_tracing_data,

		.ordered_events	 = true,

	};

	struct perf_data data = {
@@ -1585,6 +1604,7 @@ static int __cmd_report(bool display_info) 
	symbol_conf.sort_by_name = true;

	symbol__init(&session->header.env);



	if (!data.is_pipe) {

		if (!perf_session__has_traces(session, "lock record"))

			goto out_delete;
@@ -1597,6 +1617,7 @@ static int __cmd_report(bool display_info) 
			pr_err("Initializing perf session tracepoint handlers failed\n");

			goto out_delete;

		}

	}



	if (setup_output_field(false, output_fields))

		goto out_delete;
@@ -1633,9 +1654,12 @@ static int __cmd_contention(int argc, const char **argv) 
{

	int err = -EINVAL;

	struct perf_tool eops = {

		.attr		 = perf_event__process_attr,

		.event_update	 = process_event_update,

		.sample		 = process_sample_event,

		.comm		 = perf_event__process_comm,

		.mmap		 = perf_event__process_mmap,

		.tracing_data	 = perf_event__process_tracing_data,

		.ordered_events	 = true,

	};

	struct perf_data data = {
@@ -1698,7 +1722,7 @@ static int __cmd_contention(int argc, const char **argv) 
			pr_err("lock contention BPF setup failed\n");

			goto out_delete;

		}

	} else {

	} else if (!data.is_pipe) {

		if (!perf_session__has_traces(session, "lock record"))

			goto out_delete;

tools/perf/tests/shell/lock_contention.sh

+14 −1
Original line number Diff line number Diff line
@@ -53,7 +53,7 @@ test_bpf() 


	if ! perf lock con -b true > /dev/null 2>&1 ; then

		echo "[Skip] No BPF support"

		exit

		return

	fi



	# the perf lock contention output goes to the stderr
@@ -65,9 +65,22 @@ test_bpf() 
	fi

}



test_record_concurrent()

{

	echo "Testing perf lock record and perf lock contention at the same time"

	perf lock record -o- -- perf bench sched messaging 2> /dev/null | \

	perf lock contention -i- -E 1 -q 2> ${result}

	if [ $(cat "${result}" | wc -l) != "1" ]; then

		echo "[Fail] Recorded result count is not 1:" $(cat "${result}" | wc -l)

		err=1

		exit

	fi

}



check



test_record

test_bpf

test_record_concurrent



exit ${err}