linux-kernel - Re: [PATCH v1 2/3] perf record: apply affinity masks when reading mmap buffers

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Date:   Wed, 12 Dec 2018 13:15:38 +0100
From:   Jiri Olsa <jolsa@...hat.com>
To:     Alexey Budankov <alexey.budankov@...ux.intel.com>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Andi Kleen <ak@...ux.intel.com>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1 2/3] perf record: apply affinity masks when reading
 mmap buffers

On Wed, Dec 12, 2018 at 10:40:22AM +0300, Alexey Budankov wrote:

SNIP

>  int perf_mmap__mmap(struct perf_mmap *map, struct mmap_params *mp, int fd, int cpu)
>  {
> +	int c, nr_cpus, node;
>  	/*
>  	 * The last one will be done at perf_mmap__consume(), so that we
>  	 * make sure we don't prevent tools from consuming every last event in
> @@ -344,6 +369,17 @@ int perf_mmap__mmap(struct perf_mmap *map, struct mmap_params *mp, int fd, int c
>  	map->cpu = cpu;
>  
>  	CPU_ZERO(&map->affinity_mask);
> +	if (mp->affinity == PERF_AFFINITY_NODE && cpu__max_node() > 1) {
> +		nr_cpus = cpu_map__nr(mp->cpu_map);
> +		node = cpu__get_node(map->cpu);
> +		for (c = 0; c < nr_cpus; c++) {
> +			if (cpu__get_node(c) == node) {
> +				CPU_SET(c, &map->affinity_mask);
> +			}
> +		}
> +	} else if (mp->affinity == PERF_AFFINITY_CPU) {
> +		CPU_SET(map->cpu, &map->affinity_mask);
> +	}

won't both of this end up in same mask?

jirka