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

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Message-ID: <20190227131045.GB18893@krava>
Date:   Wed, 27 Feb 2019 14:10:45 +0100
From:   Jiri Olsa <jolsa@...hat.com>
To:     "Jin, Yao" <yao.jin@...ux.intel.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 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