Re: [PATCH 5/5] perf diff: Fix -o/--order option behavior

[Jiri Olsa <jolsa@redhat.com>]

On Wed, Jan 07, 2015 at 04:47:06PM +0900, Namhyung Kim wrote:
> On Sun, Jan 04, 2015 at 07:26:56PM +0100, Jiri Olsa wrote:
> > On Sat, Dec 27, 2014 at 02:06:33PM +0900, Namhyung Kim wrote:
> > 
> > SNIP
> > 
> > > +		return 0;
> > > +
> > > +	fmt = zalloc(sizeof(*fmt));
> > > +	if (fmt == NULL) {
> > > +		pr_err("Memory allocation failed\n");
> > > +		return -1;
> > > +	}
> > > +
> > > +	fmt->cmp      = hist_entry__cmp_nop;
> > > +	fmt->collapse = hist_entry__cmp_nop;
> > > +
> > > +	switch (compute) {
> > > +	case COMPUTE_DELTA:
> > > +		fmt->sort = hist_entry__cmp_delta_idx;
> > > +		break;
> > > +	case COMPUTE_RATIO:
> > > +		fmt->sort = hist_entry__cmp_ratio_idx;
> > > +		break;
> > > +	case COMPUTE_WEIGHTED_DIFF:
> > > +		fmt->sort = hist_entry__cmp_wdiff_idx;
> > > +		break;
> > > +	default:
> > > +		BUG_ON(1);
> > > +	}
> > > +
> > > +	list_add(&fmt->sort_list, &perf_hpp__sort_list);
> > > +	return 0;
> > 
> > so the first 'fmt' which gets to sorting is the one for
> > data__files[sort_idx] file, that sounds good..
> > 
> > but as the sorting goes through all the perf_hpp__sort_list list,
> > it will hit the 'sort_idx' data again.. should you disable sort
> > function for its 'fmt' then?
> 
> Do you really think it's needed?
> 
> Yes, it'll be called twice but I think it's a relatively rare case as
> most entries will be sorted by the sort_idx and baseline columns.

I did not think it through completely.. thats why I asked ;-)

but I think you're right and it's not a big deal, maybe just
add some comment that this is happening and we dont think
it's too bad.. or something like that ;-)

thanks,
jirka