Commit 27e9769a authored by Alexey Budankov's avatar Alexey Budankov Committed by Arnaldo Carvalho de Melo
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perf stat: Introduce --control fd:ctl-fd[,ack-fd] options 



Introduce --control fd:ctl-fd[,ack-fd] options to pass open file
descriptors numbers from command line. Extend perf-stat.txt file with
--control fd:ctl-fd[,ack-fd] options description. Document possible
usage model introduced by --control fd:ctl-fd[,ack-fd] options by
providing example bash shell script.

Signed-off-by: default avatarAlexey Budankov <alexey.budankov@linux.intel.com>
Acked-by: default avatarJiri Olsa <jolsa@redhat.com>
Acked-by: default avatarNamhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/feabd5cf-0155-fb0a-4587-c71571f2d517@linux.intel.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent b1aa3db2

tools/perf/Documentation/perf-stat.txt

+39 −0
Original line number Diff line number Diff line
@@ -176,6 +176,45 @@ with it. --append may be used here. Examples: 
     3>results  perf stat --log-fd 3          -- $cmd

     3>>results perf stat --log-fd 3 --append -- $cmd



--control fd:ctl-fd[,ack-fd]

Listen on ctl-fd descriptor for command to control measurement ('enable': enable events,

'disable': disable events). Measurements can be started with events disabled using

--delay=-1 option. Optionally send control command completion ('ack\n') to ack-fd descriptor

to synchronize with the controlling process. Example of bash shell script to enable and

disable events during measurements:



#!/bin/bash



ctl_dir=/tmp/



ctl_fifo=${ctl_dir}perf_ctl.fifo

test -p ${ctl_fifo} && unlink ${ctl_fifo}

mkfifo ${ctl_fifo}

exec {ctl_fd}<>${ctl_fifo}



ctl_ack_fifo=${ctl_dir}perf_ctl_ack.fifo

test -p ${ctl_ack_fifo} && unlink ${ctl_ack_fifo}

mkfifo ${ctl_ack_fifo}

exec {ctl_fd_ack}<>${ctl_ack_fifo}



perf stat -D -1 -e cpu-cycles -a -I 1000       \

          --control fd:${ctl_fd},${ctl_fd_ack} \

          -- sleep 30 &

perf_pid=$!



sleep 5  && echo 'enable' >&${ctl_fd} && read -u ${ctl_fd_ack} e1 && echo "enabled(${e1})"

sleep 10 && echo 'disable' >&${ctl_fd} && read -u ${ctl_fd_ack} d1 && echo "disabled(${d1})"



exec {ctl_fd_ack}>&-

unlink ${ctl_ack_fifo}



exec {ctl_fd}>&-

unlink ${ctl_fifo}



wait -n ${perf_pid}

exit $?





--pre::

--post::

	Pre and post measurement hooks, e.g.:

tools/perf/builtin-stat.c

+39 −1
Original line number Diff line number Diff line
@@ -188,6 +188,8 @@ static struct perf_stat_config stat_config = { 
	.metric_only_len	= METRIC_ONLY_LEN,

	.walltime_nsecs_stats	= &walltime_nsecs_stats,

	.big_num		= true,

	.ctl_fd			= -1,

	.ctl_fd_ack		= -1

};



static bool cpus_map_matched(struct evsel *a, struct evsel *b)
@@ -867,7 +869,7 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx) 
		perf_evlist__start_workload(evsel_list);

		enable_counters();



		if (interval || timeout)

		if (interval || timeout || evlist__ctlfd_initialized(evsel_list))

			status = dispatch_events(forks, timeout, interval, &times);

		if (child_pid != -1) {

			if (timeout)
@@ -1039,6 +1041,33 @@ static int parse_metric_groups(const struct option *opt, 
					 &stat_config.metric_events);

}



static int parse_control_option(const struct option *opt,

				const char *str,

				int unset __maybe_unused)

{

	char *comma = NULL, *endptr = NULL;

	struct perf_stat_config *config = (struct perf_stat_config *)opt->value;



	if (strncmp(str, "fd:", 3))

		return -EINVAL;



	config->ctl_fd = strtoul(&str[3], &endptr, 0);

	if (endptr == &str[3])

		return -EINVAL;



	comma = strchr(str, ',');

	if (comma) {

		if (endptr != comma)

			return -EINVAL;



		config->ctl_fd_ack = strtoul(comma + 1, &endptr, 0);

		if (endptr == comma + 1 || *endptr != '\0')

			return -EINVAL;

	}



	return 0;

}



static struct option stat_options[] = {

	OPT_BOOLEAN('T', "transaction", &transaction_run,

		    "hardware transaction statistics"),
@@ -1140,6 +1169,10 @@ static struct option stat_options[] = { 
		"libpfm4 event selector. use 'perf list' to list available events",

		parse_libpfm_events_option),

#endif

	OPT_CALLBACK(0, "control", &stat_config, "fd:ctl-fd[,ack-fd]",

		     "Listen on ctl-fd descriptor for command to control measurement ('enable': enable events, 'disable': disable events).\n"

		     "\t\t\t  Optionally send control command completion ('ack\\n') to ack-fd descriptor.",

		      parse_control_option),

	OPT_END()

};
@@ -2309,6 +2342,9 @@ int cmd_stat(int argc, const char **argv) 
	signal(SIGALRM, skip_signal);

	signal(SIGABRT, skip_signal);



	if (evlist__initialize_ctlfd(evsel_list, stat_config.ctl_fd, stat_config.ctl_fd_ack))

		goto out;



	status = 0;

	for (run_idx = 0; forever || run_idx < stat_config.run_count; run_idx++) {

		if (stat_config.run_count != 1 && verbose > 0)
@@ -2328,6 +2364,8 @@ int cmd_stat(int argc, const char **argv) 
	if (!forever && status != -1 && (!interval || stat_config.summary))

		print_counters(NULL, argc, argv);



	evlist__finalize_ctlfd(evsel_list);



	if (STAT_RECORD) {

		/*

		 * We synthesize the kernel mmap record just so that older tools

tools/perf/util/stat.h

+2 −0
Original line number Diff line number Diff line
@@ -133,6 +133,8 @@ struct perf_stat_config { 
	struct perf_cpu_map		*cpus_aggr_map;

	u64			*walltime_run;

	struct rblist		 metric_events;

	int			 ctl_fd;

	int			 ctl_fd_ack;

};



void perf_stat__set_big_num(int set);