Re: [PATCH v2 1/3] perf util: Move block_pair_cmp to block-info

[Jin, Yao]

On 1/7/2020 5:57 PM, Jiri Olsa wrote:
> On Tue, Jan 07, 2020 at 03:45:23AM +0800, Jin Yao wrote:
> > block_pair_cmp() is a function which is used to compare
> > two blocks. Moving it from builtin-diff.c to block-info.c
> > to let it be used by other builtins.
> >
> > In block_pair_cmp, there is a minor change. It checks valid
> > for map, dso and sym first. If they are invalid, we will not
> > compare the address because the address might not make sense.
>
> please separate the change as well, it's hard to track
> what you did when the whole function is moved

Got it, thanks! I will separate this too.

> >   v2:
> >   ---
> >   New patch created in v2
> >
> > Signed-off-by: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
> > ---
> >   tools/perf/builtin-diff.c    | 17 -----------------
> >   tools/perf/util/block-info.c | 23 +++++++++++++++++++++++
> >   tools/perf/util/block-info.h |  2 ++
> >   3 files changed, 25 insertions(+), 17 deletions(-)
> >
> > diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
> > index f8b6ae557d8b..5ff1e21082cb 100644
> > --- a/tools/perf/builtin-diff.c
> > +++ b/tools/perf/builtin-diff.c
> > @@ -572,23 +572,6 @@ static void init_block_hist(struct block_hist *bh)
> >   	bh->valid = true;
> >   }
> >   
> > -static int block_pair_cmp(struct hist_entry *a, struct hist_entry *b)
> > -{
> > -	struct block_info *bi_a = a->block_info;
> > -	struct block_info *bi_b = b->block_info;
> > -	int cmp;
> > -
> > -	if (!bi_a->sym || !bi_b->sym)
> > -		return -1;
> > -
> > -	cmp = strcmp(bi_a->sym->name, bi_b->sym->name);
> > -
> > -	if ((!cmp) && (bi_a->start == bi_b->start) && (bi_a->end == bi_b->end))
> > -		return 0;
> > -
> > -	return -1;
> > -}
> > -
> >   static struct hist_entry *get_block_pair(struct hist_entry *he,
> >   					 struct hists *hists_pair)
> >   {
> > diff --git a/tools/perf/util/block-info.c b/tools/perf/util/block-info.c
> > index c4b030bf6ec2..18a445938681 100644
> > --- a/tools/perf/util/block-info.c
> > +++ b/tools/perf/util/block-info.c
> > @@ -475,3 +475,26 @@ float block_info__total_cycles_percent(struct hist_entry *he)
> >   
> >   	return 0.0;
> >   }
> > +
> > +int block_pair_cmp(struct hist_entry *pair, struct hist_entry *he)
> > +{
> > +	struct block_info *bi_p = pair->block_info;
> > +	struct block_info *bi_h = he->block_info;
> > +	struct map_symbol *ms_p = &pair->ms;
> > +	struct map_symbol *ms_h = &he->ms;
> > +	int cmp;
> > +
> > +	if (!ms_p->map || !ms_p->map->dso || !ms_p->sym ||
> > +	    !ms_h->map || !ms_h->map->dso || !ms_h->sym) {
> > +		return -1;
> > +	}
> > +
> > +	cmp = strcmp(ms_p->sym->name, ms_h->sym->name);
> > +	if (cmp)
> > +		return -1;
>
> should this return cmp? also you don't mention this change in the changelog

Yes, return cmp should be OK.

It's changed from "strcmp(bi_a->sym->name, bi_b->sym->name)" to 
"strcmp(ms_p->sym->name, ms_h->sym->name)" is because we don't need an 
additional checking for bi_a->sym and bi_b->sym.

If we use "strcmp(bi_a->sym->name, bi_b->sym->name)" here, I think we'd 
better check the sym first. I will mention that in changelog.

Thanks
Jin Yao

> thanks,
> jirka