Re: [PATCH v1 3/8] perf stat: introduce control descriptors and --ctl-fd[-ack] options

[Jiri Olsa]

On Fri, Mar 27, 2020 at 11:47:40AM +0300, Alexey Budankov wrote:
> 
> Introduce control file descriptors and --ctl-fd[-ack] options to pass
> control descriptors from command line. Extend --delay option with -1
> value to start collection in paused mode to be resumed later by resume
> command provided via control file descriptor.

could you please separate those 2 changes?  also for record change

thanks,
jirka

> 
> Signed-off-by: Alexey Budankov <alexey.budankov@xxxxxxxxxxxxxxx>
> ---
>  tools/perf/builtin-stat.c | 28 ++++++++++++++++++++++++----
>  tools/perf/util/evlist.h  |  3 +++
>  tools/perf/util/stat.h    |  4 +++-
>  3 files changed, 30 insertions(+), 5 deletions(-)
> 
> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> index ec053dc1e35c..0a1b79fd3f48 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -187,6 +187,8 @@ 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 inline void diff_timespec(struct timespec *r, struct timespec *a,
> @@ -373,16 +375,26 @@ static void process_interval(void)
>  
>  static void enable_counters(void)
>  {
> -	if (stat_config.initial_delay)
> +	if (stat_config.initial_delay < 0) {
> +		pr_info(PERF_EVLIST__PAUSED_MSG);
> +		return;
> +	}
> +
> +	if (stat_config.initial_delay > 0) {
> +		pr_info(PERF_EVLIST__PAUSED_MSG);
>  		usleep(stat_config.initial_delay * USEC_PER_MSEC);
> +	}
>  
>  	/*
>  	 * We need to enable counters only if:
>  	 * - we don't have tracee (attaching to task or cpu)
>  	 * - we have initial delay configured
>  	 */
> -	if (!target__none(&target) || stat_config.initial_delay)
> +	if (!target__none(&target) || stat_config.initial_delay) {
>  		evlist__enable(evsel_list);
> +		if (stat_config.initial_delay > 0)
> +			pr_info(PERF_EVLIST__RESUMED_MSG);
> +	}
>  }
>  
>  static void disable_counters(void)
> @@ -912,8 +924,8 @@ static struct option stat_options[] = {
>  		     "aggregate counts per thread", AGGR_THREAD),
>  	OPT_SET_UINT(0, "per-node", &stat_config.aggr_mode,
>  		     "aggregate counts per numa node", AGGR_NODE),
> -	OPT_UINTEGER('D', "delay", &stat_config.initial_delay,
> -		     "ms to wait before starting measurement after program start"),
> +	OPT_INTEGER('D', "delay", &stat_config.initial_delay,
> +		     "ms to wait before starting measurement after program start (-1: start paused"),
>  	OPT_CALLBACK_NOOPT(0, "metric-only", &stat_config.metric_only, NULL,
>  			"Only print computed metrics. No raw values", enable_metric_only),
>  	OPT_BOOLEAN(0, "topdown", &topdown_run,
> @@ -933,6 +945,10 @@ static struct option stat_options[] = {
>  		    "Use with 'percore' event qualifier to show the event "
>  		    "counts of one hardware thread by sum up total hardware "
>  		    "threads of same physical core"),
> +	OPT_INTEGER(0, "ctl-fd", &stat_config.ctl_fd,
> +		    "Listen on fd descriptor for command to control measurement ('r': resume, 'p': pause)"),
> +	OPT_INTEGER(0, "ctl-fd-ack", &stat_config.ctl_fd_ack,
> +		    "Send control command completion ('a') to fd ack descriptor"),
>  	OPT_END()
>  };
>  
> @@ -2129,6 +2145,8 @@ int cmd_stat(int argc, const char **argv)
>  	signal(SIGALRM, skip_signal);
>  	signal(SIGABRT, skip_signal);
>  
> +	perf_evlist__initialize_ctlfd(evsel_list, stat_config.ctl_fd, stat_config.ctl_fd_ack);
> +
>  	status = 0;
>  	for (run_idx = 0; forever || run_idx < stat_config.run_count; run_idx++) {
>  		if (stat_config.run_count != 1 && verbose > 0)
> @@ -2148,6 +2166,8 @@ int cmd_stat(int argc, const char **argv)
>  	if (!forever && status != -1 && !interval)
>  		print_counters(NULL, argc, argv);
>  
> +	perf_evlist__finalize_ctlfd(evsel_list);
> +
>  	if (STAT_RECORD) {
>  		/*
>  		 * We synthesize the kernel mmap record just so that older tools
> diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
> index a94b2993fafc..c91368483074 100644
> --- a/tools/perf/util/evlist.h
> +++ b/tools/perf/util/evlist.h
> @@ -369,6 +369,9 @@ enum evlist_ctl_cmd {
>  	CTL_CMD_ACK = 'a'
>  };
>  
> +#define PERF_EVLIST__RESUMED_MSG "Monitoring resumed\n"
> +#define PERF_EVLIST__PAUSED_MSG  "Monitoring paused\n"
> +
>  int perf_evlist__initialize_ctlfd(struct evlist *evlist, int ctl_fd, int ctl_fd_ack);
>  int perf_evlist__finalize_ctlfd(struct evlist *evlist);
>  int perf_evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd);
> diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h
> index b4fdfaa7f2c0..0b0fa3a2cde2 100644
> --- a/tools/perf/util/stat.h
> +++ b/tools/perf/util/stat.h
> @@ -113,7 +113,7 @@ struct perf_stat_config {
>  	FILE			*output;
>  	unsigned int		 interval;
>  	unsigned int		 timeout;
> -	unsigned int		 initial_delay;
> +	int			 initial_delay;
>  	unsigned int		 unit_width;
>  	unsigned int		 metric_only_len;
>  	int			 times;
> @@ -130,6 +130,8 @@ 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 update_stats(struct stats *stats, u64 val);
> -- 
> 2.24.1
> 
>