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From:   Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Date:   Wed, 4 Dec 2019 10:48:36 -0300
To:     Alexey Budankov <alexey.budankov@linux.intel.com>
Cc:     Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Andi Kleen <ak@linux.intel.com>,
        linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v5 3/3] perf record: adapt affinity to machines with
 #CPUs > 1K
Message-ID: <20191204134836.GA31283@kernel.org>
References: <d1aead99-474a-46d3-36be-36dbb8e5581b@linux.intel.com>
 <96d7e2ff-ce8b-c1e0-d52c-aa59ea96f0ea@linux.intel.com>
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In-Reply-To: <96d7e2ff-ce8b-c1e0-d52c-aa59ea96f0ea@linux.intel.com>
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Em Tue, Dec 03, 2019 at 02:45:27PM +0300, Alexey Budankov escreveu:
> 
> Use struct mmap_cpu_mask type for tool's thread and mmap data
> buffers to overcome current 1024 CPUs mask size limitation of
> cpu_set_t type.
> 
> Currently glibc cpu_set_t type has internal mask size limit
> of 1024 CPUs. Moving to struct mmap_cpu_mask type allows
> overcoming that limit. tools bitmap API is used to manipulate
> objects of struct mmap_cpu_mask type.

Had to apply this to fix the build in some toolchains/arches:

[acme@quaco perf]$ git diff
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 7bc83755ef8c..4c301466101b 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -2508,10 +2508,10 @@ int cmd_record(int argc, const char **argv)
                rec->affinity_mask.nbits = cpu__max_cpu();
                rec->affinity_mask.bits = bitmap_alloc(rec->affinity_mask.nbits);
                if (!rec->affinity_mask.bits) {
-                       pr_err("Failed to allocate thread mask for %ld cpus\n", rec->affinity_mask.nbits);
+                       pr_err("Failed to allocate thread mask for %zd cpus\n", rec->affinity_mask.nbits);
                        return -ENOMEM;
                }
-               pr_debug2("thread mask[%ld]: empty\n", rec->affinity_mask.nbits);
+               pr_debug2("thread mask[%zd]: empty\n", rec->affinity_mask.nbits);
        }

        err = record__auxtrace_init(rec);


> Reported-by: Andi Kleen <ak@linux.intel.com>
> Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
> ---
>  tools/perf/builtin-record.c | 28 ++++++++++++++++++++++------
>  tools/perf/util/mmap.c      | 28 ++++++++++++++++++++++------
>  tools/perf/util/mmap.h      |  2 +-
>  3 files changed, 45 insertions(+), 13 deletions(-)
> 
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index fb19ef63cc35..7bc83755ef8c 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -62,6 +62,7 @@
>  #include <linux/string.h>
>  #include <linux/time64.h>
>  #include <linux/zalloc.h>
> +#include <linux/bitmap.h>
>  
>  struct switch_output {
>  	bool		 enabled;
> @@ -93,7 +94,7 @@ struct record {
>  	bool			timestamp_boundary;
>  	struct switch_output	switch_output;
>  	unsigned long long	samples;
> -	cpu_set_t		affinity_mask;
> +	struct mmap_cpu_mask	affinity_mask;
>  	unsigned long		output_max_size;	/* = 0: unlimited */
>  };
>  
> @@ -961,10 +962,15 @@ static struct perf_event_header finished_round_event = {
>  static void record__adjust_affinity(struct record *rec, struct mmap *map)
>  {
>  	if (rec->opts.affinity != PERF_AFFINITY_SYS &&
> -	    !CPU_EQUAL(&rec->affinity_mask, &map->affinity_mask)) {
> -		CPU_ZERO(&rec->affinity_mask);
> -		CPU_OR(&rec->affinity_mask, &rec->affinity_mask, &map->affinity_mask);
> -		sched_setaffinity(0, sizeof(rec->affinity_mask), &rec->affinity_mask);
> +	    !bitmap_equal(rec->affinity_mask.bits, map->affinity_mask.bits,
> +			  rec->affinity_mask.nbits)) {
> +		bitmap_zero(rec->affinity_mask.bits, rec->affinity_mask.nbits);
> +		bitmap_or(rec->affinity_mask.bits, rec->affinity_mask.bits,
> +			  map->affinity_mask.bits, rec->affinity_mask.nbits);
> +		sched_setaffinity(0, MMAP_CPU_MASK_BYTES(&rec->affinity_mask),
> +				  (cpu_set_t *)rec->affinity_mask.bits);
> +		if (verbose == 2)
> +			mmap_cpu_mask__scnprintf(&rec->affinity_mask, "thread");
>  	}
>  }
>  
> @@ -2433,7 +2439,6 @@ int cmd_record(int argc, const char **argv)
>  # undef REASON
>  #endif
>  
> -	CPU_ZERO(&rec->affinity_mask);
>  	rec->opts.affinity = PERF_AFFINITY_SYS;
>  
>  	rec->evlist = evlist__new();
> @@ -2499,6 +2504,16 @@ int cmd_record(int argc, const char **argv)
>  
>  	symbol__init(NULL);
>  
> +	if (rec->opts.affinity != PERF_AFFINITY_SYS) {
> +		rec->affinity_mask.nbits = cpu__max_cpu();
> +		rec->affinity_mask.bits = bitmap_alloc(rec->affinity_mask.nbits);
> +		if (!rec->affinity_mask.bits) {
> +			pr_err("Failed to allocate thread mask for %ld cpus\n", rec->affinity_mask.nbits);
> +			return -ENOMEM;
> +		}
> +		pr_debug2("thread mask[%ld]: empty\n", rec->affinity_mask.nbits);
> +	}
> +
>  	err = record__auxtrace_init(rec);
>  	if (err)
>  		goto out;
> @@ -2613,6 +2628,7 @@ int cmd_record(int argc, const char **argv)
>  
>  	err = __cmd_record(&record, argc, argv);
>  out:
> +	bitmap_free(rec->affinity_mask.bits);
>  	evlist__delete(rec->evlist);
>  	symbol__exit();
>  	auxtrace_record__free(rec->itr);
> diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
> index 43c12b4a3e17..832d2cb94b2c 100644
> --- a/tools/perf/util/mmap.c
> +++ b/tools/perf/util/mmap.c
> @@ -219,6 +219,8 @@ static void perf_mmap__aio_munmap(struct mmap *map __maybe_unused)
>  
>  void mmap__munmap(struct mmap *map)
>  {
> +	bitmap_free(map->affinity_mask.bits);
> +
>  	perf_mmap__aio_munmap(map);
>  	if (map->data != NULL) {
>  		munmap(map->data, mmap__mmap_len(map));
> @@ -227,7 +229,7 @@ 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;
> @@ -240,17 +242,23 @@ 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;
> +
>  	if (mp->affinity == PERF_AFFINITY_NODE && cpu__max_node() > 1)
>  		build_node_mask(cpu__get_node(map->core.cpu), &map->affinity_mask);
>  	else if (mp->affinity == PERF_AFFINITY_CPU)
> -		CPU_SET(map->core.cpu, &map->affinity_mask);
> +		set_bit(map->core.cpu, map->affinity_mask.bits);
> +
> +	return 0;
>  }
>  
>  int mmap__mmap(struct mmap *map, struct mmap_params *mp, int fd, int cpu)
> @@ -261,7 +269,15 @@ int mmap__mmap(struct mmap *map, struct mmap_params *mp, int fd, int cpu)
>  		return -1;
>  	}
>  
> -	perf_mmap__setup_affinity_mask(map, mp);
> +	if (mp->affinity != PERF_AFFINITY_SYS &&
> +		perf_mmap__setup_affinity_mask(map, mp)) {
> +		pr_debug2("failed to alloc mmap affinity mask, error %d\n",
> +			  errno);
> +		return -1;
> +	}
> +
> +	if (verbose == 2)
> +		mmap_cpu_mask__scnprintf(&map->affinity_mask, "mmap");
>  
>  	map->core.flush = mp->flush;
>  
> diff --git a/tools/perf/util/mmap.h b/tools/perf/util/mmap.h
> index ef51667fabcb..9d5f589f02ae 100644
> --- a/tools/perf/util/mmap.h
> +++ b/tools/perf/util/mmap.h
> @@ -40,7 +40,7 @@ struct mmap {
>  		int		 nr_cblocks;
>  	} aio;
>  #endif
> -	cpu_set_t	affinity_mask;
> +	struct mmap_cpu_mask	affinity_mask;
>  	void		*data;
>  	int		comp_level;
>  };
> -- 
> 2.20.1
> 

-- 

- Arnaldo