linux-kernel - Re: [PATCH 1/2] perf top: Decay all events in the evlist

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Date:   Wed, 28 Aug 2019 09:49:49 -0300
From:   Arnaldo Carvalho de Melo <arnaldo.melo@...il.com>
To:     Namhyung Kim <namhyung@...nel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>, Jiri Olsa <jolsa@...hat.com>
Subject: Re: [PATCH 1/2] perf top: Decay all events in the evlist

Em Wed, Aug 28, 2019 at 08:15:54AM +0900, Namhyung Kim escreveu:
> Currently perf top only decays entries in a selected evsel.  I don't
> know whether it's intended (maybe due to performance reason?) but
> anyway it might show incorrect output when event group is used since
> users will see leader event is decayed but others are not.
> 
> This patch moves the decay code into evlist__resort_hists() so that
> stdio and tui code shared the logic.
> 
> Signed-off-by: Namhyung Kim <namhyung@...nel.org>
> ---
>  tools/perf/builtin-top.c | 38 +++++++++++++-------------------------
>  1 file changed, 13 insertions(+), 25 deletions(-)
> 
> diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
> index 5970723cd55a..9d3059d2029d 100644
> --- a/tools/perf/builtin-top.c
> +++ b/tools/perf/builtin-top.c
> @@ -264,13 +264,23 @@ static void perf_top__show_details(struct perf_top *top)
>  	pthread_mutex_unlock(&notes->lock);
>  }
>  
> -static void evlist__resort_hists(struct evlist *evlist)
> +static void evlist__resort_hists(struct perf_top *t)

Since this now operates on the perf_top struct, I'll rename it to
perf_top__resort_hists(), ok? No need to send an updated patch.

- Arnaldo

>  {
> +	struct evlist *evlist = t->evlist;
>  	struct evsel *pos;
>  
>  	evlist__for_each_entry(evlist, pos) {
>  		struct hists *hists = evsel__hists(pos);
>  
> +		if (evlist->enabled) {
> +			if (t->zero) {
> +				hists__delete_entries(hists);
> +			} else {
> +				hists__decay_entries(hists, t->hide_user_symbols,
> +						     t->hide_kernel_symbols);
> +			}
> +		}
> +
>  		hists__collapse_resort(hists, NULL);
>  
>  		/* Non-group events are considered as leader */
> @@ -319,16 +329,7 @@ static void perf_top__print_sym_table(struct perf_top *top)
>  		return;
>  	}
>  
> -	if (top->evlist->enabled) {
> -		if (top->zero) {
> -			hists__delete_entries(hists);
> -		} else {
> -			hists__decay_entries(hists, top->hide_user_symbols,
> -					     top->hide_kernel_symbols);
> -		}
> -	}
> -
> -	evlist__resort_hists(top->evlist);
> +	evlist__resort_hists(top);
>  
>  	hists__output_recalc_col_len(hists, top->print_entries - printed);
>  	putchar('\n');
> @@ -576,24 +577,11 @@ static bool perf_top__handle_keypress(struct perf_top *top, int c)
>  static void perf_top__sort_new_samples(void *arg)
>  {
>  	struct perf_top *t = arg;
> -	struct evsel *evsel = t->sym_evsel;
> -	struct hists *hists;
>  
>  	if (t->evlist->selected != NULL)
>  		t->sym_evsel = t->evlist->selected;
>  
> -	hists = evsel__hists(evsel);
> -
> -	if (t->evlist->enabled) {
> -		if (t->zero) {
> -			hists__delete_entries(hists);
> -		} else {
> -			hists__decay_entries(hists, t->hide_user_symbols,
> -					     t->hide_kernel_symbols);
> -		}
> -	}
> -
> -	evlist__resort_hists(t->evlist);
> +	evlist__resort_hists(t);
>  
>  	if (t->lost || t->drop)
>  		pr_warning("Too slow to read ring buffer (change period (-c/-F) or limit CPUs (-C)\n");
> -- 
> 2.23.0.187.g17f5b7556c-goog

-- 

- Arnaldo