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

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Date:   Wed, 27 Feb 2019 22:24:25 +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 9:10 PM, Jiri Olsa wrote:
> On Wed, Feb 27, 2019 at 08:51:44PM +0800, Jin, Yao wrote:
>>
>>
>> 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.
> 
> why do we need to have time range set if there's no --time
> option set by user?
> 
> jirka
> 

Yes, that could be refined if no --time option set by user. I think I 
can add a new patch to fix these for perf report/script.

Thanks
Jin Yao