linux-kernel - Re: [PATCH 12/54] tools/perf: replace bitmap_weight with bitmap

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Message-ID: <Ygu58J67Il0KuPYq@kernel.org>
Date:   Tue, 15 Feb 2022 11:34:24 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Yury Norov <yury.norov@...il.com>
Cc:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Michał Mirosław <mirq-linux@...e.qmqm.pl>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Peter Zijlstra <peterz@...radead.org>,
        David Laight <David.Laight@...lab.com>,
        Joe Perches <joe@...ches.com>, Dennis Zhou <dennis@...nel.org>,
        Emil Renner Berthing <kernel@...il.dk>,
        Nicholas Piggin <npiggin@...il.com>,
        Matti Vaittinen <matti.vaittinen@...rohmeurope.com>,
        Alexey Klimov <aklimov@...hat.com>,
        linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...hat.com>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        linux-perf-users@...r.kernel.org
Subject: Re: [PATCH 12/54] tools/perf: replace bitmap_weight with
 bitmap_empty where appropriate

Em Sun, Jan 23, 2022 at 10:38:43AM -0800, Yury Norov escreveu:
> Some code in builtin-c2c.c calls bitmap_weight() to check if any bit of
> a given bitmap is set. It's better to use bitmap_empty() in that case
> because bitmap_empty() stops traversing the bitmap as soon as it finds
> first set bit, while bitmap_weight() counts all bits unconditionally.

Thanks, applied.

- Arnaldo

 
> Signed-off-by: Yury Norov <yury.norov@...il.com>
> ---
>  tools/perf/builtin-c2c.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
> index 77dd4afacca4..14f787c67140 100644
> --- a/tools/perf/builtin-c2c.c
> +++ b/tools/perf/builtin-c2c.c
> @@ -1080,7 +1080,7 @@ node_entry(struct perf_hpp_fmt *fmt __maybe_unused, struct perf_hpp *hpp,
>  		bitmap_zero(set, c2c.cpus_cnt);
>  		bitmap_and(set, c2c_he->cpuset, c2c.nodes[node], c2c.cpus_cnt);
>  
> -		if (!bitmap_weight(set, c2c.cpus_cnt)) {
> +		if (bitmap_empty(set, c2c.cpus_cnt)) {
>  			if (c2c.node_info == 1) {
>  				ret = scnprintf(hpp->buf, hpp->size, "%21s", " ");
>  				advance_hpp(hpp, ret);
> @@ -1944,7 +1944,7 @@ static int set_nodestr(struct c2c_hist_entry *c2c_he)
>  	if (c2c_he->nodestr)
>  		return 0;
>  
> -	if (bitmap_weight(c2c_he->nodeset, c2c.nodes_cnt)) {
> +	if (!bitmap_empty(c2c_he->nodeset, c2c.nodes_cnt)) {
>  		len = bitmap_scnprintf(c2c_he->nodeset, c2c.nodes_cnt,
>  				      buf, sizeof(buf));
>  	} else {
> -- 
> 2.30.2

-- 

- Arnaldo