netdev - Re: [PATCH v2 4/6] perf cpumap: More cpu map reuse by merge.

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Date:   Wed, 30 Mar 2022 17:34:42 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Ian Rogers <irogers@...gle.com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Mike Leach <mike.leach@...aro.org>,
        Leo Yan <leo.yan@...aro.org>,
        John Garry <john.garry@...wei.com>,
        Will Deacon <will@...nel.org>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>,
        Martin KaFai Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        John Fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...nel.org>,
        Kajol Jain <kjain@...ux.ibm.com>,
        James Clark <james.clark@....com>,
        German Gomez <german.gomez@....com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Riccardo Mancini <rickyman7@...il.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Alexey Bayduraev <alexey.v.bayduraev@...ux.intel.com>,
        Alexander Antonov <alexander.antonov@...ux.intel.com>,
        linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
        coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org,
        netdev@...r.kernel.org, bpf@...r.kernel.org,
        Stephane Eranian <eranian@...gle.com>
Subject: Re: [PATCH v2 4/6] perf cpumap: More cpu map reuse by merge.

Em Mon, Mar 28, 2022 at 04:26:46PM -0700, Ian Rogers escreveu:
> perf_cpu_map__merge will reuse one of its arguments if they are equal or
> the other argument is NULL. The arguments could be reused if it is known
> one set of values is a subset of the other. For example, a map of 0-1
> and a map of just 0 when merged yields the map of 0-1. Currently a new
> map is created rather than adding a reference count to the original 0-1
> map.

Thanks, applied.

- Arnaldo

 
> Signed-off-by: Ian Rogers <irogers@...gle.com>
> ---
>  tools/lib/perf/cpumap.c | 15 +++++----------
>  1 file changed, 5 insertions(+), 10 deletions(-)
> 
> diff --git a/tools/lib/perf/cpumap.c b/tools/lib/perf/cpumap.c
> index 23701024e0c0..384d5e076ee4 100644
> --- a/tools/lib/perf/cpumap.c
> +++ b/tools/lib/perf/cpumap.c
> @@ -355,17 +355,12 @@ struct perf_cpu_map *perf_cpu_map__merge(struct perf_cpu_map *orig,
>  	int i, j, k;
>  	struct perf_cpu_map *merged;
>  
> -	if (!orig && !other)
> -		return NULL;
> -	if (!orig) {
> -		perf_cpu_map__get(other);
> -		return other;
> -	}
> -	if (!other)
> -		return orig;
> -	if (orig->nr == other->nr &&
> -	    !memcmp(orig->map, other->map, orig->nr * sizeof(struct perf_cpu)))
> +	if (perf_cpu_map__is_subset(orig, other))
>  		return orig;
> +	if (perf_cpu_map__is_subset(other, orig)) {
> +		perf_cpu_map__put(orig);
> +		return perf_cpu_map__get(other);
> +	}
>  
>  	tmp_len = orig->nr + other->nr;
>  	tmp_cpus = malloc(tmp_len * sizeof(struct perf_cpu));
> -- 
> 2.35.1.1021.g381101b075-goog

-- 

- Arnaldo