linux-kernel - Re: [PATCH v1 4/8] perf stat: implement resume and pause control commands handling

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Date:   Thu, 2 Apr 2020 16:17:40 +0200
From:   Jiri Olsa <jolsa@...hat.com>
To:     Alexey Budankov <alexey.budankov@...ux.intel.com>
Cc:     Arnaldo Carvalho de Melo <acme@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Andi Kleen <ak@...ux.intel.com>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1 4/8] perf stat: implement resume and pause control
 commands handling

On Fri, Mar 27, 2020 at 11:48:31AM +0300, Alexey Budankov wrote:

SNIP

>  
> -	if (interval) {
> -		ts.tv_sec  = interval / USEC_PER_MSEC;
> -		ts.tv_nsec = (interval % USEC_PER_MSEC) * NSEC_PER_MSEC;
> -	} else if (timeout) {
> -		ts.tv_sec  = timeout / USEC_PER_MSEC;
> -		ts.tv_nsec = (timeout % USEC_PER_MSEC) * NSEC_PER_MSEC;
> -	} else {
> -		ts.tv_sec  = 1;
> -		ts.tv_nsec = 0;
> -	}
> -
>  	if (forks) {
>  		if (perf_evlist__prepare_workload(evsel_list, &target, argv, is_pipe,
>  						  workload_exec_failed_signal) < 0) {
> @@ -688,18 +745,10 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx)
>  		perf_evlist__start_workload(evsel_list);
>  		enable_counters();
>  
> -		if (interval || timeout) {
> -			while (!waitpid(child_pid, &status, WNOHANG)) {
> -				nanosleep(&ts, NULL);
> -				if (timeout)
> -					break;
> -				process_interval();
> -				if (interval_count && !(--times))
> -					break;
> -			}
> -		}
> -		if (child_pid != -1)
> +		if (stat_config.ctl_fd == -1 && !interval && !timeout)
>  			wait4(child_pid, &status, 0, &stat_config.ru_data);
> +		else
> +			status = handle_events(child_pid, &stat_config);
>  
>  		if (workload_exec_errno) {
>  			const char *emsg = str_error_r(workload_exec_errno, msg, sizeof(msg));
> @@ -711,18 +760,7 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx)
>  			psignal(WTERMSIG(status), argv[0]);
>  	} else {
>  		enable_counters();
> -		while (!done) {
> -			nanosleep(&ts, NULL);
> -			if (!is_target_alive(&target, evsel_list->core.threads))
> -				break;
> -			if (timeout)
> -				break;
> -			if (interval) {
> -				process_interval();
> -				if (interval_count && !(--times))
> -					break;
> -			}
> -		}

could you please separate the change to have:
  - factor out the above too loops to the new function
  - adding control fds handling to that function

so it's more obvious we don't break anything

thanks,
jirka

> +		handle_events(-1, &stat_config);
>  	}
>  
>  	disable_counters();
> -- 
> 2.24.1
> 
>