linux-kernel - Re: [PATCH v4 3/9] perf evlist: Maintain evlist->all

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Message-ID: <20191106163407.GN30214@krava>
Date:   Wed, 6 Nov 2019 17:34:07 +0100
From:   Jiri Olsa <jolsa@...hat.com>
To:     Andi Kleen <andi@...stfloor.org>
Cc:     acme@...nel.org, jolsa@...nel.org, linux-kernel@...r.kernel.org,
        Andi Kleen <ak@...ux.intel.com>
Subject: Re: [PATCH v4 3/9] perf evlist: Maintain evlist->all_cpus

On Mon, Nov 04, 2019 at 04:25:16PM -0800, Andi Kleen wrote:
> From: Andi Kleen <ak@...ux.intel.com>
> 
> Maintain a cpumap in the evlist that is the union of all the cpus
> of the events.
> 
> This needs a cpumap merge operation. To make the merge operation
> work efficiently maintain the cpumap in a sorted state.
> 
> The sorting is also needed for the affinity loop changes later.
> 
> Signed-off-by: Andi Kleen <ak@...ux.intel.com>
> ---
>  tools/perf/lib/cpumap.c                  | 42 ++++++++++++++++++++++++
>  tools/perf/lib/evlist.c                  |  1 +
>  tools/perf/lib/include/internal/evlist.h |  1 +
>  tools/perf/lib/include/perf/cpumap.h     |  2 ++
>  4 files changed, 46 insertions(+)
> 
> diff --git a/tools/perf/lib/cpumap.c b/tools/perf/lib/cpumap.c
> index 2ca1fafa620d..5ca26a9d318f 100644
> --- a/tools/perf/lib/cpumap.c
> +++ b/tools/perf/lib/cpumap.c
> @@ -68,6 +68,11 @@ static struct perf_cpu_map *cpu_map__default_new(void)
>  	return cpus;
>  }
>  
> +static int cmp_int(const void *a, const void *b)
> +{
> +	return *(const int *)a - *(const int*)b;
> +}
> +
>  static struct perf_cpu_map *cpu_map__trim_new(int nr_cpus, int *tmp_cpus)
>  {
>  	size_t payload_size = nr_cpus * sizeof(int);
> @@ -76,6 +81,7 @@ static struct perf_cpu_map *cpu_map__trim_new(int nr_cpus, int *tmp_cpus)
>  	if (cpus != NULL) {
>  		cpus->nr = nr_cpus;
>  		memcpy(cpus->map, tmp_cpus, payload_size);
> +		qsort(cpus->map, nr_cpus, sizeof(int), cmp_int);
>  		refcount_set(&cpus->refcnt, 1);
>  	}
 
please move the sort into separate change

>  
> @@ -272,3 +278,39 @@ int perf_cpu_map__max(struct perf_cpu_map *map)
>  
>  	return max;
>  }
> +
> +struct perf_cpu_map *perf_cpu_map__update(struct perf_cpu_map *orig,
> +					  struct perf_cpu_map *other)
> +{

it's more like perf_cpu_map__merge, right?

> +	int *tmp_cpus;
> +	int tmp_len;
> +	int i, j, k;
> +	struct perf_cpu_map *merged;
> +
> +	if (!orig) {
> +		perf_cpu_map__get(other);
> +		return other;
> +	}
> +	if (orig->nr == other->nr &&
> +	    !memcmp(orig->map, other->map, orig->nr * sizeof(int)))
> +		return orig;
> +	tmp_len = orig->nr + other->nr;
> +	tmp_cpus = malloc(tmp_len * sizeof(int));
> +	if (!tmp_cpus)
> +		return NULL;
> +	i = j = k = 0;
> +	while (i < orig->nr && j < other->nr) {
> +		if (orig->map[i] <= other->map[j])
> +			tmp_cpus[k++] = orig->map[i++];
> +		else
> +			tmp_cpus[k++] = other->map[j++];
> +	}
> +	while (i < orig->nr)
> +		tmp_cpus[k++] = orig->map[i++];
> +	while (j < other->nr)
> +		tmp_cpus[k++] = other->map[j++];
> +	assert(k < tmp_len);
> +	merged = cpu_map__trim_new(k, tmp_cpus);
> +	free(tmp_cpus);
> +	return merged;
> +}

this is great function for automated test, please add

thanks,
jirka