RE: [PATCH V2 5/6] perf,tools: caculate and save freq/CPU%/CORE_BUSY% in he_stat

[Liang, Kan]

> > -481,6 +486,32 @@ iter_add_next_nop_entry(struct hist_entry_iter
> *iter
> > __maybe_unused,  }
> >
> >  static int
> > +iter_add_single_freq_perf_entry(struct hist_entry_iter *iter, struct
> > +addr_location *al) {
> > +	struct perf_evsel *evsel = iter->evsel;
> > +	struct perf_sample *sample = iter->sample;
> > +	struct hist_entry *he;
> > +	struct freq_perf_info info = {0};
> > +	u64 *data = sample->freq_perf_data;
> > +
> > +	if (data[FREQ_PERF_REF_CYCLES] > 0)
> > +		info.freq = (data[FREQ_PERF_CYCLES] * cpu_max_freq) /
> data[FREQ_PERF_REF_CYCLES];
> > +	if (data[FREQ_PERF_TSC] > 0)
> > +		info.cpu_u = (100 * data[FREQ_PERF_REF_CYCLES]) /
> data[FREQ_PERF_TSC];
> > +	if (data[FREQ_PERF_MPERF] > 0)
> > +		info.core_busy = (100 * data[FREQ_PERF_APERF]) /
> > +data[FREQ_PERF_MPERF];
> 
> seems to me the new iterator is too big gun for this, why not initialize
> 'struct freq_perf_info' in iter_prepare_normal_entry ?
> 

Yes, we can initialize it in normal process.
But we only need the freq_perf_info when "--show-freq-perf" is set.
For most of the cases, it wastes time to calculate the unused information
for each sample. That could impact the performance for processing. 

Thanks,
Kan
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