Re: [PATCH v2 4/7] perf diff: Use hists to manage basic blocks per symbol

[Jin, Yao]

On 6/5/2019 7:44 PM, Jiri Olsa wrote:
> On Mon, Jun 03, 2019 at 10:36:14PM +0800, Jin Yao wrote:
>
> SNIP
>
> >   		data__for_each_file_new(i, d) {
> >   			pair = get_pair_data(he, d);
> >   			if (!pair)
> > @@ -510,6 +683,9 @@ static void hists__precompute(struct hists *hists)
> >   			case COMPUTE_WEIGHTED_DIFF:
> >   				compute_wdiff(he, pair);
> >   				break;
> > +			case COMPUTE_CYCLES:
> > +				process_block_per_sym(pair, d);
> > +				break;
> >   			default:
> >   				BUG_ON(1);
> >   			}
> > @@ -713,6 +889,14 @@ hist_entry__cmp_wdiff_idx(struct perf_hpp_fmt *fmt __maybe_unused,
> >   					   sort_compute);
> >   }
> >   
> > +static int64_t
> > +hist_entry__cmp_cycles_idx(struct perf_hpp_fmt *fmt __maybe_unused,
> > +			   struct hist_entry *left __maybe_unused,
> > +			   struct hist_entry *right __maybe_unused)
> > +{
> > +	return 0;
> > +}
>
> this is hist_entry__cmp_nop.. please use it instead and
> explain in comment why for COMPUTE_CYCLES we need the
> default sort
>
> jirka

fmt->sort should be set otherwise since fmt->sort will be called without 
checking valid, the crash happens. Yes, I should use hist_entry__cmp_nop 
instead, and will add some comments for COMPUTE_CYCLES.

Thanks
Jin Yao