linux-kernel - Re: [PATCH v2 1/3] perf diff: Support --time filter option

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Message-ID: <2eecb3cf-1dcc-f98f-1ca5-f9c29bd8fd8f@linux.intel.com>
Date:   Wed, 27 Feb 2019 20:51:44 +0800
From:   "Jin, Yao" <yao.jin@...ux.intel.com>
To:     Jiri Olsa <jolsa@...hat.com>
Cc:     acme@...nel.org, jolsa@...nel.org, peterz@...radead.org,
        mingo@...hat.com, alexander.shishkin@...ux.intel.com,
        Linux-kernel@...r.kernel.org, ak@...ux.intel.com,
        kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH v2 1/3] perf diff: Support --time filter option



On 2/27/2019 5:28 PM, Jiri Olsa wrote:
> On Tue, Feb 26, 2019 at 08:11:07PM +0800, Jin Yao wrote:
> 
> SNIP
> 
>> +		.ordered_events = true,
>> +		.ordering_requires_timestamps = true,
>> +	},
>>   };
>>   
>>   static struct perf_evsel *evsel_match(struct perf_evsel *evsel,
>> @@ -771,19 +788,136 @@ static void data__free(struct data__file *d)
>>   	}
>>   }
>>   
>> +static int parse_time_range(struct data__file *d,
>> +			    struct perf_time_interval *ptime_range,
>> +			    const char *time_str)
>> +{
>> +	if (perf_time__parse_str(ptime_range,
>> +				 time_str) != 0) {
>> +		if (d->session->evlist->first_sample_time == 0 &&
>> +		    d->session->evlist->last_sample_time == 0) {
>> +			pr_err("HINT: no first/last sample time found in perf data.\n"
>> +			       "Please use latest perf binary to execute 'perf record'\n"
>> +			       "(if '--buildid-all' is enabled, please set '--timestamp-boundary').\n");
>> +			return -EINVAL;
>> +		}
>> +
>> +		pdiff.range_num = perf_time__percent_parse_str(
>> +				ptime_range, pdiff.range_size, time_str,
>> +				d->session->evlist->first_sample_time,
>> +				d->session->evlist->last_sample_time);
>> +
>> +		if (pdiff.range_num < 0) {
>> +			pr_err("Invalid time string\n");
>> +			return -EINVAL;
>> +		}
>> +	} else {
>> +		pdiff.range_num = 1;
> 
> I dont understand why we set range_num to 1 if there's
> not time option set.. it should be 0 and we should take
> no action in diff__process_sample_event, right?
> 
> then I checked the report code and we do the same,
> could we fix that? I'm assuming we don't need any
> time check if the time option is not set.. please
> correct me if I miss something
> 
> jirka
> 

We support multiple complicated time strings. :(

In parse_time_range(), perf_time__parse_str() returns 0 if the time 
string is a simple start/stop format. So next, we set the range_num to 
1. If the time string contains multiple time percent ranges (e.g. 
"10%/1,10%/2,..."), perf_time__parse_str() will return with error (<0), 
then we will continue checking with perf_time__percent_parse_str().

So when range_num is set to 1, it just means it's the simple time string.

Thanks
Jin Yao