Re: [PATCH 2/4] perf hist: Simplify hist printing logic for group events

From: Namhyung Kim
Date: Thu Feb 15 2024 - 00:18:22 EST


On Wed, Feb 14, 2024 at 3:57 PM Ian Rogers <irogers@xxxxxxxxxx> wrote:
>
> On Mon, Feb 12, 2024 at 11:53 PM Namhyung Kim <namhyung@xxxxxxxxxx> wrote:
> >
> > It can uses an array to save the period (or percent) values for member
> > events and print them together in a loop. This simplify the logic to
> > handle missing samples in members with zero values.
> >
> > No functional change intended.
> >
> > Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
> > ---
> > tools/perf/ui/hist.c | 55 +++++++++++++++++---------------------------
> > 1 file changed, 21 insertions(+), 34 deletions(-)
> >
> > diff --git a/tools/perf/ui/hist.c b/tools/perf/ui/hist.c
> > index 2bf959d08354..5f4c110d840f 100644
> > --- a/tools/perf/ui/hist.c
> > +++ b/tools/perf/ui/hist.c
> > @@ -33,6 +33,7 @@ static int __hpp__fmt(struct perf_hpp *hpp, struct hist_entry *he,
> > char *buf = hpp->buf;
> > size_t size = hpp->size;
> >
> > + /* print stand-alone or group leader events separately */
> > if (fmt_percent) {
> > double percent = 0.0;
> > u64 total = hists__total_period(hists);
> > @@ -45,12 +46,19 @@ static int __hpp__fmt(struct perf_hpp *hpp, struct hist_entry *he,
> > ret = hpp__call_print_fn(hpp, print_fn, fmt, len, get_field(he));
> >
> > if (evsel__is_group_event(evsel)) {
> > - int prev_idx, idx_delta;
> > + int idx;
> > struct hist_entry *pair;
> > int nr_members = evsel->core.nr_members;
> > + union {
> > + u64 period;
> > + double percent;
> > + } *val;
> >
> > - prev_idx = evsel__group_idx(evsel);
> > + val = calloc(nr_members, sizeof(*val));
> > + if (val == NULL)
> > + return 0;
>
> Looks good, but should this return value be negative to indicate an
> error? Snprintf gives a negative result on error, its result is
> sometimes returned from hpp__fmt_acc, as is this result.

Sounds good, will change.

Thanks,
Namhyung

>
> >
> > + /* collect values in the group members */
> > list_for_each_entry(pair, &he->pairs.head, pairs.node) {
> > u64 period = get_field(pair);
> > u64 total = hists__total_period(pair->hists);
> > @@ -59,47 +67,26 @@ static int __hpp__fmt(struct perf_hpp *hpp, struct hist_entry *he,
> > continue;
> >
> > evsel = hists_to_evsel(pair->hists);
> > - idx_delta = evsel__group_idx(evsel) - prev_idx - 1;
> > -
> > - while (idx_delta--) {
> > - /*
> > - * zero-fill group members in the middle which
> > - * have no sample
> > - */
> > - if (fmt_percent) {
> > - ret += hpp__call_print_fn(hpp, print_fn,
> > - fmt, len, 0.0);
> > - } else {
> > - ret += hpp__call_print_fn(hpp, print_fn,
> > - fmt, len, 0ULL);
> > - }
> > - }
> > -
> > - if (fmt_percent) {
> > - ret += hpp__call_print_fn(hpp, print_fn, fmt, len,
> > - 100.0 * period / total);
> > - } else {
> > - ret += hpp__call_print_fn(hpp, print_fn, fmt,
> > - len, period);
> > - }
> > + idx = evsel__group_idx(evsel);
> >
> > - prev_idx = evsel__group_idx(evsel);
> > + if (fmt_percent)
> > + val[idx].percent = 100.0 * period / total;
> > + else
> > + val[idx].period = period;
> > }
> >
> > - idx_delta = nr_members - prev_idx - 1;
> > -
> > - while (idx_delta--) {
> > - /*
> > - * zero-fill group members at last which have no sample
> > - */
> > + /* idx starts from 1 to skip the leader event */
> > + for (idx = 1; idx < nr_members; idx++) {
> > if (fmt_percent) {
> > ret += hpp__call_print_fn(hpp, print_fn,
> > - fmt, len, 0.0);
> > + fmt, len, val[idx].percent);
> > } else {
> > ret += hpp__call_print_fn(hpp, print_fn,
> > - fmt, len, 0ULL);
> > + fmt, len, val[idx].period);
> > }
> > }
> > +
> > + free(val);
> > }
> >
> > /*
> > --
> > 2.43.0.687.g38aa6559b0-goog
> >