linux-kernel - Re: [PATCH v8 09/13] perf stat: implement control commands handling

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Message-ID: <5d6bab4b-d743-609e-e08c-8eabcb9adfef@linux.intel.com>
Date:   Wed, 24 Jun 2020 17:10:10 +0300
From:   Alexey Budankov <alexey.budankov@...ux.intel.com>
To:     Jiri Olsa <jolsa@...hat.com>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        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 v8 09/13] perf stat: implement control commands handling


On 23.06.2020 17:54, Jiri Olsa wrote:
> On Wed, Jun 17, 2020 at 11:41:30AM +0300, Alexey Budankov wrote:
> 
> SNIP
> 
>>  
>>  	while (1) {
>>  		if (forks)
>> @@ -581,8 +617,17 @@ static int dispatch_events(bool forks, int timeout, int interval, int *times, st
>>  		if (done || stop || child)
>>  			break;
>>  
>> -		nanosleep(ts, NULL);
>> -		stop = process_timeout(timeout, interval, times);
>> +		clock_gettime(CLOCK_MONOTONIC, &time_start);
>> +		if (!(evlist__poll(evsel_list, time_to_sleep) > 0)) { /* poll timeout or EINTR */
>> +			stop = process_timeout(timeout, interval, times);
>> +			time_to_sleep = sleep_time;
>> +		} else { /* fd revent */
>> +			stop = process_evlist(evsel_list, interval, times);
>> +			clock_gettime(CLOCK_MONOTONIC, &time_stop);
>> +			diff_timespec(&time_diff, &time_stop, &time_start);
>> +			time_to_sleep -= time_diff.tv_sec * MSEC_PER_SEC +
>> +					time_diff.tv_nsec / NSEC_PER_MSEC;
> 
> should we check time_to_sleep > time_diff first?

Probably and if time_diff > time_to_sleep then time_to_sleep = 0 ?

~Alexey

> 
> jirka
>