linux-kernel - Re: [PATCH 2/4] perf hist: Simplify __hpp_fmt() using hpp_fmt

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Date: Tue, 4 Jun 2024 12:18:47 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Namhyung Kim <namhyung@...nel.org>
Cc: Ian Rogers <irogers@...gle.com>, Kan Liang <kan.liang@...ux.intel.com>,
	Jiri Olsa <jolsa@...nel.org>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...nel.org>, LKML <linux-kernel@...r.kernel.org>,
	linux-perf-users@...r.kernel.org
Subject: Re: [PATCH 2/4] perf hist: Simplify __hpp_fmt() using hpp_fmt_data

On Mon, Jun 03, 2024 at 03:44:10PM -0700, Namhyung Kim wrote:
> The struct hpp_fmt_data is to keep the values for each group members so
> it doesn't need to check the event index in the group.
> 
> Signed-off-by: Namhyung Kim <namhyung@...nel.org>
> ---
>  tools/perf/ui/hist.c | 75 +++++++++++++++++++++-----------------------
>  1 file changed, 36 insertions(+), 39 deletions(-)
> 
> diff --git a/tools/perf/ui/hist.c b/tools/perf/ui/hist.c
> index e30fcb1e87e7..539978c95cfd 100644
> --- a/tools/perf/ui/hist.c
> +++ b/tools/perf/ui/hist.c
> @@ -46,65 +46,62 @@ static int __hpp__fmt_print(struct perf_hpp *hpp, struct hists *hists, u64 val,
>  	return hpp__call_print_fn(hpp, print_fn, fmt, len, val);
>  }
>  
> +struct hpp_fmt_data {
> +	struct hists *hists;
> +	u64 val;
> +	int samples;
> +};

Can we try to avoid vague terms like 'data' and use a hopefully more
clear 'hpp_fmt_value' instead?

>  static int __hpp__fmt(struct perf_hpp *hpp, struct hist_entry *he,
>  		      hpp_field_fn get_field, const char *fmt, int len,
>  		      hpp_snprint_fn print_fn, enum perf_hpp_fmt_type fmtype)
>  {
> -	int ret;
> +	int ret = 0;
>  	struct hists *hists = he->hists;
>  	struct evsel *evsel = hists_to_evsel(hists);
> +	struct evsel *pos;
>  	char *buf = hpp->buf;
>  	size_t size = hpp->size;
> +	int i, nr_members = 1;
> +	struct hpp_fmt_data *data;

Here we then use:

	struct hpp_fmt_value *values;

> +
> +	if (evsel__is_group_event(evsel))
> +		nr_members = evsel->core.nr_members;
> +
> +	data = calloc(nr_members, sizeof(*data));
> +	if (data == NULL)
> +		return 0;


> +
> +	i = 0;
> +	for_each_group_evsel(pos, evsel)
> +		data[i++].hists = evsel__hists(pos);
>  
> -	ret = __hpp__fmt_print(hpp, hists, get_field(he), he->stat.nr_events,
> -			       fmt, len, print_fn, fmtype);
> +	data[0].val = get_field(he);
> +	data[0].samples = he->stat.nr_events;
>  
>  	if (evsel__is_group_event(evsel)) {
> -		int prev_idx, idx_delta;
>  		struct hist_entry *pair;
> -		int nr_members = evsel->core.nr_members;
> -
> -		prev_idx = evsel__group_idx(evsel);
>  
>  		list_for_each_entry(pair, &he->pairs.head, pairs.node) {
> -			u64 period = get_field(pair);
> -			u64 total = hists__total_period(pair->hists);
> -			int nr_samples = pair->stat.nr_events;
> -
> -			if (!total)
> -				continue;
> +			for (i = 0; i < nr_members; i++) {
> +				if (data[i].hists != pair->hists)
> +					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 samples, pair->hists is not correct but it's
> -				 * fine since the value is 0.
> -				 */
> -				ret += __hpp__fmt_print(hpp, pair->hists, 0, 0,
> -							fmt, len, print_fn, fmtype);
> +				data[i].val = get_field(pair);
> +				data[i].samples = pair->stat.nr_events;
> +				break;
>  			}
> -
> -			ret += __hpp__fmt_print(hpp, pair->hists, period, nr_samples,
> -						fmt, len, print_fn, fmtype);
> -
> -			prev_idx = evsel__group_idx(evsel);
>  		}
> +	}
>  
> -		idx_delta = nr_members - prev_idx - 1;
> -
> -		while (idx_delta--) {
> -			/*
> -			 * zero-fill group members at last which have no sample.
> -			 * the hists is not correct but it's fine like above.
> -			 */
> -			ret += __hpp__fmt_print(hpp, evsel__hists(evsel), 0, 0,
> -						fmt, len, print_fn, fmtype);
> -		}
> +	for (i = 0; i < nr_members; i++) {
> +		ret += __hpp__fmt_print(hpp, data[i].hists, data[i].val,
> +					data[i].samples, fmt, len,
> +					print_fn, fmtype);
>  	}
>  
> +	free(data);
> +
>  	/*
>  	 * Restore original buf and size as it's where caller expects
>  	 * the result will be saved.
> -- 
> 2.45.1.288.g0e0cd299f1-goog