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Date:   Mon, 31 Jan 2022 18:00:30 -0300
From:   Arnaldo Carvalho de Melo <acme@kernel.org>
To:     Alexey Bayduraev <alexey.v.bayduraev@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>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Andi Kleen <ak@linux.intel.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Alexander Antonov <alexander.antonov@linux.intel.com>,
        Alexei Budankov <abudankov@huawei.com>,
        Riccardo Mancini <rickyman7@gmail.com>
Subject: Re: [PATCH v13 01/16] perf record: Introduce thread affinity and
 mmap masks
Message-ID: <YfhN7kTLECDwgPLh@kernel.org>
References: <cover.1642440724.git.alexey.v.bayduraev@linux.intel.com>
 <9042bf7daf988e17e17e6acbf5d29590bde869cd.1642440724.git.alexey.v.bayduraev@linux.intel.com>
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Em Mon, Jan 17, 2022 at 09:34:21PM +0300, Alexey Bayduraev escreveu:
> Introduce affinity and mmap thread masks. Thread affinity mask
> defines CPUs that a thread is allowed to run on. Thread maps
> mask defines mmap data buffers the thread serves to stream
> profiling data from.
> 
> Acked-by: Andi Kleen <ak@linux.intel.com>
> Acked-by: Namhyung Kim <namhyung@gmail.com>
> Reviewed-by: Riccardo Mancini <rickyman7@gmail.com>
> Tested-by: Riccardo Mancini <rickyman7@gmail.com>
> Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>

Some simplifications I added here while reviewing this patchkit:

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 41998f2140cd5119..53b88c8600624237 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -2213,35 +2213,33 @@ static int record__parse_affinity(const struct option *opt, const char *str, int
 
 static int record__mmap_cpu_mask_alloc(struct mmap_cpu_mask *mask, int nr_bits)
 {
-	mask->nbits = nr_bits;
 	mask->bits = bitmap_zalloc(mask->nbits);
 	if (!mask->bits)
 		return -ENOMEM;
 
+	mask->nbits = nr_bits;
 	return 0;
 }
 
 static void record__mmap_cpu_mask_free(struct mmap_cpu_mask *mask)
 {
 	bitmap_free(mask->bits);
+	mask->bits = NULL;
 	mask->nbits = 0;
 }
 
 static int record__thread_mask_alloc(struct thread_mask *mask, int nr_bits)
 {
-	int ret;
+	int ret = record__mmap_cpu_mask_alloc(&mask->maps, nr_bits);
 
-	ret = record__mmap_cpu_mask_alloc(&mask->maps, nr_bits);
 	if (ret) {
 		mask->affinity.bits = NULL;
 		return ret;
 	}
 
 	ret = record__mmap_cpu_mask_alloc(&mask->affinity, nr_bits);
-	if (ret) {
+	if (ret)
 		record__mmap_cpu_mask_free(&mask->maps);
-		mask->maps.bits = NULL;
-	}
 
 	return ret;
 }
@@ -2733,18 +2731,14 @@ struct option *record_options = __record_options;
 
 static void record__mmap_cpu_mask_init(struct mmap_cpu_mask *mask, struct perf_cpu_map *cpus)
 {
-	int c;
-
-	for (c = 0; c < cpus->nr; c++)
+	for (int c = 0; c < cpus->nr; c++)
 		set_bit(cpus->map[c].cpu, mask->bits);
 }
 
 static void record__free_thread_masks(struct record *rec, int nr_threads)
 {
-	int t;
-
 	if (rec->thread_masks)
-		for (t = 0; t < nr_threads; t++)
+		for (int t = 0; t < nr_threads; t++)
 			record__thread_mask_free(&rec->thread_masks[t]);
 
 	zfree(&rec->thread_masks);
@@ -2752,7 +2746,7 @@ static void record__free_thread_masks(struct record *rec, int nr_threads)
 
 static int record__alloc_thread_masks(struct record *rec, int nr_threads, int nr_bits)
 {
-	int t, ret;
+	int ret;
 
 	rec->thread_masks = zalloc(nr_threads * sizeof(*(rec->thread_masks)));
 	if (!rec->thread_masks) {
@@ -2760,7 +2754,7 @@ static int record__alloc_thread_masks(struct record *rec, int nr_threads, int nr
 		return -ENOMEM;
 	}
 
-	for (t = 0; t < nr_threads; t++) {
+	for (int t = 0; t < nr_threads; t++) {
 		ret = record__thread_mask_alloc(&rec->thread_masks[t], nr_bits);
 		if (ret) {
 			pr_err("Failed to allocate thread masks[%d]\n", t);
@@ -2778,9 +2772,7 @@ static int record__alloc_thread_masks(struct record *rec, int nr_threads, int nr
 
 static int record__init_thread_default_masks(struct record *rec, struct perf_cpu_map *cpus)
 {
-	int ret;
-
-	ret = record__alloc_thread_masks(rec, 1, cpu__max_cpu().cpu);
+	int ret = record__alloc_thread_masks(rec, 1, cpu__max_cpu().cpu);
 	if (ret)
 		return ret;
 

> ---
>  tools/perf/builtin-record.c | 123 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 123 insertions(+)
> 
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index bb716c953d02..41998f2140cd 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -87,6 +87,11 @@ struct switch_output {
>  	int		 cur_file;
>  };
>  
> +struct thread_mask {
> +	struct mmap_cpu_mask	maps;
> +	struct mmap_cpu_mask	affinity;
> +};
> +
>  struct record {
>  	struct perf_tool	tool;
>  	struct record_opts	opts;
> @@ -112,6 +117,8 @@ struct record {
>  	struct mmap_cpu_mask	affinity_mask;
>  	unsigned long		output_max_size;	/* = 0: unlimited */
>  	struct perf_debuginfod	debuginfod;
> +	int			nr_threads;
> +	struct thread_mask	*thread_masks;
>  };
>  
>  static volatile int done;
> @@ -2204,6 +2211,47 @@ static int record__parse_affinity(const struct option *opt, const char *str, int
>  	return 0;
>  }
>  
> +static int record__mmap_cpu_mask_alloc(struct mmap_cpu_mask *mask, int nr_bits)
> +{
> +	mask->nbits = nr_bits;
> +	mask->bits = bitmap_zalloc(mask->nbits);
> +	if (!mask->bits)
> +		return -ENOMEM;
> +
> +	return 0;
> +}
> +
> +static void record__mmap_cpu_mask_free(struct mmap_cpu_mask *mask)
> +{
> +	bitmap_free(mask->bits);
> +	mask->nbits = 0;
> +}
> +
> +static int record__thread_mask_alloc(struct thread_mask *mask, int nr_bits)
> +{
> +	int ret;
> +
> +	ret = record__mmap_cpu_mask_alloc(&mask->maps, nr_bits);
> +	if (ret) {
> +		mask->affinity.bits = NULL;
> +		return ret;
> +	}
> +
> +	ret = record__mmap_cpu_mask_alloc(&mask->affinity, nr_bits);
> +	if (ret) {
> +		record__mmap_cpu_mask_free(&mask->maps);
> +		mask->maps.bits = NULL;
> +	}
> +
> +	return ret;
> +}
> +
> +static void record__thread_mask_free(struct thread_mask *mask)
> +{
> +	record__mmap_cpu_mask_free(&mask->maps);
> +	record__mmap_cpu_mask_free(&mask->affinity);
> +}
> +
>  static int parse_output_max_size(const struct option *opt,
>  				 const char *str, int unset)
>  {
> @@ -2683,6 +2731,73 @@ static struct option __record_options[] = {
>  
>  struct option *record_options = __record_options;
>  
> +static void record__mmap_cpu_mask_init(struct mmap_cpu_mask *mask, struct perf_cpu_map *cpus)
> +{
> +	int c;
> +
> +	for (c = 0; c < cpus->nr; c++)
> +		set_bit(cpus->map[c].cpu, mask->bits);
> +}
> +
> +static void record__free_thread_masks(struct record *rec, int nr_threads)
> +{
> +	int t;
> +
> +	if (rec->thread_masks)
> +		for (t = 0; t < nr_threads; t++)
> +			record__thread_mask_free(&rec->thread_masks[t]);
> +
> +	zfree(&rec->thread_masks);
> +}
> +
> +static int record__alloc_thread_masks(struct record *rec, int nr_threads, int nr_bits)
> +{
> +	int t, ret;
> +
> +	rec->thread_masks = zalloc(nr_threads * sizeof(*(rec->thread_masks)));
> +	if (!rec->thread_masks) {
> +		pr_err("Failed to allocate thread masks\n");
> +		return -ENOMEM;
> +	}
> +
> +	for (t = 0; t < nr_threads; t++) {
> +		ret = record__thread_mask_alloc(&rec->thread_masks[t], nr_bits);
> +		if (ret) {
> +			pr_err("Failed to allocate thread masks[%d]\n", t);
> +			goto out_free;
> +		}
> +	}
> +
> +	return 0;
> +
> +out_free:
> +	record__free_thread_masks(rec, nr_threads);
> +
> +	return ret;
> +}
> +
> +static int record__init_thread_default_masks(struct record *rec, struct perf_cpu_map *cpus)
> +{
> +	int ret;
> +
> +	ret = record__alloc_thread_masks(rec, 1, cpu__max_cpu().cpu);
> +	if (ret)
> +		return ret;
> +
> +	record__mmap_cpu_mask_init(&rec->thread_masks->maps, cpus);
> +
> +	rec->nr_threads = 1;
> +
> +	return 0;
> +}
> +
> +static int record__init_thread_masks(struct record *rec)
> +{
> +	struct perf_cpu_map *cpus = rec->evlist->core.cpus;
> +
> +	return record__init_thread_default_masks(rec, cpus);
> +}
> +
>  int cmd_record(int argc, const char **argv)
>  {
>  	int err;
> @@ -2948,6 +3063,12 @@ int cmd_record(int argc, const char **argv)
>  		goto out;
>  	}
>  
> +	err = record__init_thread_masks(rec);
> +	if (err) {
> +		pr_err("Failed to initialize parallel data streaming masks\n");
> +		goto out;
> +	}
> +
>  	if (rec->opts.nr_cblocks > nr_cblocks_max)
>  		rec->opts.nr_cblocks = nr_cblocks_max;
>  	pr_debug("nr_cblocks: %d\n", rec->opts.nr_cblocks);
> @@ -2966,6 +3087,8 @@ int cmd_record(int argc, const char **argv)
>  	symbol__exit();
>  	auxtrace_record__free(rec->itr);
>  out_opts:
> +	record__free_thread_masks(rec, rec->nr_threads);
> +	rec->nr_threads = 0;
>  	evlist__close_control(rec->opts.ctl_fd, rec->opts.ctl_fd_ack, &rec->opts.ctl_fd_close);
>  	return err;
>  }
> -- 
> 2.19.0

-- 

- Arnaldo