Subject: Re: [PATCH v4 02/48] perf stat: Add aggr creators that are passed a cpu.

From: Arnaldo Carvalho de Melo <[email-masked]>
Date: Tue, 11 Jan 2022 16:33:01 -0300

Em Tue, Jan 04, 2022 at 10:13:05PM -0800, Ian Rogers escreveu:
> The cpu_map and index can get confused. Add variants of the cpu_map__get
> routines that are passed a cpu. Make the existing cpu_map__get routines
> use the new functions with a view to remove them when no longer used.
> 
> Reviewed-by: James Clark <[email-masked]>
> Signed-off-by: Ian Rogers <[email-masked]>
> ---
>  tools/perf/util/cpumap.c | 79 +++++++++++++++++++++++-----------------
>  tools/perf/util/cpumap.h |  6 ++-
>  2 files changed, 51 insertions(+), 34 deletions(-)
> 
> diff --git a/tools/perf/util/cpumap.c b/tools/perf/util/cpumap.c
> index 87d3eca9b872..49fba2c53822 100644
> --- a/tools/perf/util/cpumap.c
> +++ b/tools/perf/util/cpumap.c
> @@ -128,21 +128,23 @@ int cpu_map__get_socket_id(int cpu)
>  	return ret ?: value;
>  }
>  
> -struct aggr_cpu_id cpu_map__get_socket(struct perf_cpu_map *map, int idx,
> -					void *data __maybe_unused)
> +struct aggr_cpu_id cpu_map__get_socket_aggr_by_cpu(int cpu, void *data __maybe_unused)
>  {
> -	int cpu;
>  	struct aggr_cpu_id id = cpu_map__empty_aggr_cpu_id();
>  
> -	if (idx > map->nr)
> -		return id;
> -
> -	cpu = map->map[idx];
> -
>  	id.socket = cpu_map__get_socket_id(cpu);
>  	return id;
>  }
>  
> +struct aggr_cpu_id cpu_map__get_socket(struct perf_cpu_map *map, int idx,
> +				       void *data)
> +{
> +	if (idx < 0 || idx > map->nr)
> +		return cpu_map__empty_aggr_cpu_id();
> +
> +	return cpu_map__get_socket_aggr_by_cpu(map->map[idx], data);
> +}
> +

This 'idx < 0' wasn't in the original code nor is described in the
comment log message, please avoid doing this, this may be harmless or
even a good hardening, but either way would be interesting to have it in
a separate patch. This eases review as in the end this code is just a
refactoring, moving things around but in the end should be equivalent code.

There are a few more, please consider this and if you agree, to speed
things up I can make the changes here, if I think this won't fallout in
changes to subsequent patches touching this area.

- Arnaldo

>  static int cmp_aggr_cpu_id(const void *a_pointer, const void *b_pointer)
>  {
>  	struct aggr_cpu_id *a = (struct aggr_cpu_id *)a_pointer;
> @@ -200,15 +202,10 @@ int cpu_map__get_die_id(int cpu)
>  	return ret ?: value;
>  }
>  
> -struct aggr_cpu_id cpu_map__get_die(struct perf_cpu_map *map, int idx, void *data)
> +struct aggr_cpu_id cpu_map__get_die_aggr_by_cpu(int cpu, void *data)
>  {
> -	int cpu, die;
> -	struct aggr_cpu_id id = cpu_map__empty_aggr_cpu_id();
> -
> -	if (idx > map->nr)
> -		return id;
> -
> -	cpu = map->map[idx];
> +	struct aggr_cpu_id id;
> +	int die;
>  
>  	die = cpu_map__get_die_id(cpu);
>  	/* There is no die_id on legacy system. */
> @@ -220,7 +217,7 @@ struct aggr_cpu_id cpu_map__get_die(struct perf_cpu_map *map, int idx, void *dat
>  	 * with the socket ID and then add die to
>  	 * make a unique ID.
>  	 */
> -	id = cpu_map__get_socket(map, idx, data);
> +	id = cpu_map__get_socket_aggr_by_cpu(cpu, data);
>  	if (cpu_map__aggr_cpu_id_is_empty(id))
>  		return id;
>  
> @@ -228,6 +225,15 @@ struct aggr_cpu_id cpu_map__get_die(struct perf_cpu_map *map, int idx, void *dat
>  	return id;
>  }
>  
> +struct aggr_cpu_id cpu_map__get_die(struct perf_cpu_map *map, int idx,
> +				    void *data)
> +{
> +	if (idx < 0 || idx > map->nr)
> +		return cpu_map__empty_aggr_cpu_id();

Ditto

> +
> +	return cpu_map__get_die_aggr_by_cpu(map->map[idx], data);
> +}
> +
>  int cpu_map__get_core_id(int cpu)
>  {
>  	int value, ret = cpu__get_topology_int(cpu, "core_id", &value);
> @@ -239,20 +245,13 @@ int cpu_map__get_node_id(int cpu)
>  	return cpu__get_node(cpu);
>  }
>  
> -struct aggr_cpu_id cpu_map__get_core(struct perf_cpu_map *map, int idx, void *data)
> +struct aggr_cpu_id cpu_map__get_core_aggr_by_cpu(int cpu, void *data)
>  {
> -	int cpu;
> -	struct aggr_cpu_id id = cpu_map__empty_aggr_cpu_id();
> -
> -	if (idx > map->nr)
> -		return id;
> -
> -	cpu = map->map[idx];
> -
> -	cpu = cpu_map__get_core_id(cpu);
> +	struct aggr_cpu_id id;
> +	int core = cpu_map__get_core_id(cpu);
>  
>  	/* cpu_map__get_die returns a struct with socket and die set*/
> -	id = cpu_map__get_die(map, idx, data);
> +	id = cpu_map__get_die_aggr_by_cpu(cpu, data);
>  	if (cpu_map__aggr_cpu_id_is_empty(id))
>  		return id;
>  
> @@ -260,19 +259,33 @@ struct aggr_cpu_id cpu_map__get_core(struct perf_cpu_map *map, int idx, void *da
>  	 * core_id is relative to socket and die, we need a global id.
>  	 * So we combine the result from cpu_map__get_die with the core id
>  	 */
> -	id.core = cpu;
> +	id.core = core;
>  	return id;
> +
>  }
>  
> -struct aggr_cpu_id cpu_map__get_node(struct perf_cpu_map *map, int idx, void *data __maybe_unused)
> +struct aggr_cpu_id cpu_map__get_core(struct perf_cpu_map *map, int idx, void *data)
> +{
> +	if (idx < 0 || idx > map->nr)
> +		return cpu_map__empty_aggr_cpu_id();

Ditto

> +
> +	return cpu_map__get_core_aggr_by_cpu(map->map[idx], data);
> +}
> +
> +struct aggr_cpu_id cpu_map__get_node_aggr_by_cpu(int cpu, void *data __maybe_unused)
>  {
>  	struct aggr_cpu_id id = cpu_map__empty_aggr_cpu_id();
>  
> +	id.node = cpu_map__get_node_id(cpu);
> +	return id;
> +}
> +
> +struct aggr_cpu_id cpu_map__get_node(struct perf_cpu_map *map, int idx, void *data)
> +{
>  	if (idx < 0 || idx >= map->nr)
> -		return id;
> +		return cpu_map__empty_aggr_cpu_id();
>  
> -	id.node = cpu_map__get_node_id(map->map[idx]);
> -	return id;
> +	return cpu_map__get_node_aggr_by_cpu(map->map[idx], data);
>  }
>  
>  int cpu_map__build_socket_map(struct perf_cpu_map *cpus, struct cpu_aggr_map **sockp)
> diff --git a/tools/perf/util/cpumap.h b/tools/perf/util/cpumap.h
> index a27eeaf086e8..c62d67704425 100644
> --- a/tools/perf/util/cpumap.h
> +++ b/tools/perf/util/cpumap.h
> @@ -31,13 +31,17 @@ size_t cpu_map__snprint(struct perf_cpu_map *map, char *buf, size_t size);
>  size_t cpu_map__snprint_mask(struct perf_cpu_map *map, char *buf, size_t size);
>  size_t cpu_map__fprintf(struct perf_cpu_map *map, FILE *fp);
>  int cpu_map__get_socket_id(int cpu);
> +struct aggr_cpu_id cpu_map__get_socket_aggr_by_cpu(int cpu, void *data);
>  struct aggr_cpu_id cpu_map__get_socket(struct perf_cpu_map *map, int idx, void *data);
>  int cpu_map__get_die_id(int cpu);
> +struct aggr_cpu_id cpu_map__get_die_aggr_by_cpu(int cpu, void *data);
>  struct aggr_cpu_id cpu_map__get_die(struct perf_cpu_map *map, int idx, void *data);
>  int cpu_map__get_core_id(int cpu);
> +struct aggr_cpu_id cpu_map__get_core_aggr_by_cpu(int cpu, void *data);
>  struct aggr_cpu_id cpu_map__get_core(struct perf_cpu_map *map, int idx, void *data);
>  int cpu_map__get_node_id(int cpu);
> -struct aggr_cpu_id  cpu_map__get_node(struct perf_cpu_map *map, int idx, void *data);
> +struct aggr_cpu_id cpu_map__get_node_aggr_by_cpu(int cpu, void *data);
> +struct aggr_cpu_id cpu_map__get_node(struct perf_cpu_map *map, int idx, void *data);
>  int cpu_map__build_socket_map(struct perf_cpu_map *cpus, struct cpu_aggr_map **sockp);
>  int cpu_map__build_die_map(struct perf_cpu_map *cpus, struct cpu_aggr_map **diep);
>  int cpu_map__build_core_map(struct perf_cpu_map *cpus, struct cpu_aggr_map **corep);
> -- 
> 2.34.1.448.ga2b2bfdf31-goog

-- 

- Arnaldo

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