RE: [PATCH 2/2] perf,tools: check and re-organize evsel cpu maps

From: Liang, Kan
Date: Tue Jun 30 2015 - 09:43:09 EST




> > diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index
> > 6cfdee6..f179379 100644
> > --- a/tools/perf/util/evlist.c
> > +++ b/tools/perf/util/evlist.c
> > @@ -1101,6 +1101,71 @@ int perf_evlist__mmap(struct perf_evlist
> *evlist, unsigned int pages,
> > return perf_evlist__mmap_ex(evlist, pages, overwrite, 0, false); }
> >
> > +static int cmp_ids(const void *a, const void *b) {
> > + return *(int *)a - *(int *)b;
> > +}
> > +
> > +static int perf_evlist__check_evsel_cpus(struct perf_evlist *evlist,
> > +struct perf_evsel *evsel) {
> > + const struct cpu_map *cpus = evlist->cpus;
> > + const int ncpus = cpu_map__nr(evlist->cpus);
> > + int j = 0, cpu_nr = 0, tmp = 0;
> > + int i;
> > +
> > + /* ensure we process id in increasing order */
> > + qsort(evlist->cpus->map, evlist->cpus->nr, sizeof(int), cmp_ids);
>
> wouldn't sorting maps affect some other code?
>

I didn't find any bad effect after sorting the maps.
Any codes I need to check?

> > +
> > + /* find the common cpus between evsel and evlist. */
> > + for (i = 0; i < cpu_map__nr(evsel->cpus);) {
> > +
> > + if (j >= ncpus) {
> > + evsel->cpus->map[i++] = -1;
> > + continue;
> > + }
> > + for (; j < ncpus; j++) {
> > + if (cpus->map[j] < evsel->cpus->map[i])
> > + continue;
> > + if (cpus->map[j] == evsel->cpus->map[i]) {
> > + cpu_nr++;
> > + j++;
>
> hum, do you skip 1 item in cpus by j++ here and in for loop header?
>

If matching, it will break the j loop then. There is no chance to
j++ in the loop header. So I do j++ here, and it will not skip any items.

> also some easy it'd be easier to read if you identify different cpu maps
> somehow.. like evlist_cpus and evsel_cpus or such
>
OK. I will change the name.

> I have no way of testing this.. could you please add automated test for this
> one?

OK

Thanks,
Kan
>
> thanks,
> jirka
>
> > + i++;
> > + } else
> > + evsel->cpus->map[i++] = -1;
> > + break;
> > + }
> > + }
> > +
>
> SNIP
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/