linux-kernel - Re: [PATCH v1 3/3] perf record: adapt affinity to machines with #CPUs

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Message-ID: <20191122132226.GF17308@krava>
Date:   Fri, 22 Nov 2019 14:22:26 +0100
From:   Jiri Olsa <jolsa@...hat.com>
To:     Alexey Budankov <alexey.budankov@...ux.intel.com>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Andi Kleen <ak@...ux.intel.com>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1 3/3] perf record: adapt affinity to machines with
 #CPUs > 1K

On Wed, Nov 20, 2019 at 12:38:57PM +0300, Alexey Budankov wrote:

SNIP

> diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
> index 063d1b93c53d..070b1873cd45 100644
> --- a/tools/perf/util/mmap.c
> +++ b/tools/perf/util/mmap.c
> @@ -23,6 +23,7 @@
>  #include "mmap.h"
>  #include "../perf.h"
>  #include <internal/lib.h> /* page_size */
> +#include <linux/bitmap.h>
>  
>  size_t mmap__mmap_len(struct mmap *map)
>  {
> @@ -215,7 +216,7 @@ void mmap__munmap(struct mmap *map)
>  	auxtrace_mmap__munmap(&map->auxtrace_mmap);
>  }
>  
> -static void build_node_mask(int node, cpu_set_t *mask)
> +static void build_node_mask(int node, struct mmap_cpu_mask *mask)
>  {
>  	int c, cpu, nr_cpus;
>  	const struct perf_cpu_map *cpu_map = NULL;
> @@ -228,28 +229,43 @@ static void build_node_mask(int node, cpu_set_t *mask)
>  	for (c = 0; c < nr_cpus; c++) {
>  		cpu = cpu_map->map[c]; /* map c index to online cpu index */
>  		if (cpu__get_node(cpu) == node)
> -			CPU_SET(cpu, mask);
> +			set_bit(cpu, mask->bits);
>  	}
>  }
>  
> -static void perf_mmap__setup_affinity_mask(struct mmap *map, struct mmap_params *mp)
> +static int perf_mmap__setup_affinity_mask(struct mmap *map, struct mmap_params *mp)
>  {
> -	CPU_ZERO(&map->affinity_mask);
> +	map->affinity_mask.nbits = cpu__max_cpu();
> +	map->affinity_mask.bits = bitmap_alloc(map->affinity_mask.nbits);
> +	if (!map->affinity_mask.bits)
> +		return 1;

I guess this works, but please return < 0 on error

thanks,
jirka