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 18:06:47 +0300
From:   Alexey Budankov <alexey.budankov@...ux.intel.com>
To:     Jiri Olsa <jolsa@...hat.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 02.04.2020 17:17, Jiri Olsa wrote:
> 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

Accepted.

~Alexey