Re: [PATCH v3 08/12] perf record: introduce --threads=<spec> command line option

From: Namhyung Kim
Date: Fri Nov 20 2020 - 06:09:33 EST

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On Mon, Nov 16, 2020 at 03:20:26PM +0300, Alexey Budankov wrote:
>
> Provide --threads option in perf record command line interface.
> The option can have a value in the form of masks that specify
> cpus to be monitored with data streaming threads and its layout
> in system topology. The masks can be filtered using cpu mask
> provided via -C option.
>
> The specification value can be user defined list of masks. Masks
> separated by colon define cpus to be monitored by one thread and
> affinity mask of that thread is separated by slash. For example:
> <cpus mask 1>/<affinity mask 1>:<cpu mask 2>/<affinity mask 2>
> specifies parallel threads layout that consists of two threads
> with corresponding assigned cpus to be monitored.
>
> The specification value can be a string e.g. "cpu", "core" or
> "socket" meaning creation of data streaming thread for every
> cpu or core or socket to monitor distinct cpus or cpus grouped
> by core or socket.
>
> The option provided with no or empty value defaults to per-cpu
> parallel threads layout creating data streaming thread for every
> cpu being monitored.
>
> Feature design and implementation are based on prototypes [1], [2].
>
> [1] git clone https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git -b perf/record_threads
> [2] https://lore.kernel.org/lkml/20180913125450.21342-1-jolsa@xxxxxxxxxx/
>
> Suggested-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> Suggested-by: Namhyung Kim <namhyung@xxxxxxxxxx>
> Signed-off-by: Alexey Budankov <alexey.budankov@xxxxxxxxxxxxxxx>
> ---
[SNIP]
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index f5e5175da6a1..fd0587d636b2 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -3097,6 +3173,17 @@ static void record__mmap_cpu_mask_init(struct mmap_cpu_mask *mask, struct perf_c
> set_bit(cpus->map[c], mask->bits);
> }
>
> +static void record__mmap_cpu_mask_init_spec(struct mmap_cpu_mask *mask, char *mask_spec)
> +{
> + struct perf_cpu_map *cpus;
> +
> + cpus = perf_cpu_map__new(mask_spec);
> + if (cpus) {
> + record__mmap_cpu_mask_init(mask, cpus);
> + free(cpus);

Would be better to use perf_cpu_map__put().

> + }
> +}
> +
> static int record__alloc_thread_masks(struct record *rec, int nr_threads, int nr_bits)
> {
> int t, ret;
> @@ -3116,6 +3203,196 @@ static int record__alloc_thread_masks(struct record *rec, int nr_threads, int nr
>
> return 0;
> }
> +
> +static int record__init_thread_cpu_masks(struct record *rec, struct perf_cpu_map *cpus)
> +{
> + int t, ret, nr_cpus = perf_cpu_map__nr(cpus);
> +
> + ret = record__alloc_thread_masks(rec, nr_cpus, cpu__max_cpu());
> + if (ret)
> + return ret;
> +
> + rec->nr_threads = nr_cpus;
> + pr_debug("threads: nr_threads=%d\n", rec->nr_threads);
> +
> + for (t = 0; t < rec->nr_threads; t++) {
> + set_bit(cpus->map[t], rec->thread_masks[t].maps.bits);
> + pr_debug("thread_masks[%d]: maps mask [%d]\n", t, cpus->map[t]);
> + set_bit(cpus->map[t], rec->thread_masks[t].affinity.bits);
> + pr_debug("thread_masks[%d]: affinity mask [%d]\n", t, cpus->map[t]);
> + }
> +
> + return 0;
> +}
> +
> +static int record__init_thread_masks_spec(struct record *rec, struct perf_cpu_map *cpus,
> + char **maps_spec, char **affinity_spec, u32 nr_spec)
> +{
> + u32 s;
> + int ret, nr_threads = 0;
> + struct mmap_cpu_mask cpus_mask;
> + struct thread_mask thread_mask, full_mask;
> +
> + ret = record__mmap_cpu_mask_alloc(&cpus_mask, cpu__max_cpu());
> + if (ret)
> + return ret;
> + record__mmap_cpu_mask_init(&cpus_mask, cpus);
> + ret = record__thread_mask_alloc(&thread_mask, cpu__max_cpu());
> + if (ret)
> + return ret;
> + ret = record__thread_mask_alloc(&full_mask, cpu__max_cpu());
> + if (ret)
> + return ret;
> + record__thread_mask_clear(&full_mask);
> +
> + for (s = 0; s < nr_spec; s++) {
> + record__thread_mask_clear(&thread_mask);
> +
> + record__mmap_cpu_mask_init_spec(&thread_mask.maps, maps_spec[s]);
> + record__mmap_cpu_mask_init_spec(&thread_mask.affinity, affinity_spec[s]);
> +
> + if (!bitmap_and(thread_mask.maps.bits, thread_mask.maps.bits,
> + cpus_mask.bits, thread_mask.maps.nbits) ||
> + !bitmap_and(thread_mask.affinity.bits, thread_mask.affinity.bits,
> + cpus_mask.bits, thread_mask.affinity.nbits))
> + continue;
> +
> + ret = record__thread_mask_intersects(&thread_mask, &full_mask);
> + if (ret)
> + return ret;
> + record__thread_mask_or(&full_mask, &full_mask, &thread_mask);
> +
> + rec->thread_masks = realloc(rec->thread_masks,
> + (nr_threads + 1) * sizeof(struct thread_mask));
> + if (!rec->thread_masks) {
> + pr_err("Failed to allocate thread masks\n");
> + return -ENOMEM;

It'll leak previous rec->thread_masks as well as cpu/thread/full masks.

> + }
> + rec->thread_masks[nr_threads] = thread_mask;
> + pr_debug("thread_masks[%d]: addr=", nr_threads);
> + mmap_cpu_mask__scnprintf(&rec->thread_masks[nr_threads].maps, "maps");
> + pr_debug("thread_masks[%d]: addr=", nr_threads);
> + mmap_cpu_mask__scnprintf(&rec->thread_masks[nr_threads].affinity, "affinity");
> + nr_threads++;
> + ret = record__thread_mask_alloc(&thread_mask, cpu__max_cpu());
> + if (ret)
> + return ret;
> + }
> +
> + rec->nr_threads = nr_threads;
> + pr_debug("threads: nr_threads=%d\n", rec->nr_threads);
> +
> + record__mmap_cpu_mask_free(&cpus_mask);
> + record__thread_mask_free(&thread_mask);
> + record__thread_mask_free(&full_mask);
> +
> + return 0;
> +}
> +
> +static int record__init_thread_core_masks(struct record *rec, struct perf_cpu_map *cpus)
> +{
> + int ret;
> + struct cpu_topology *topo;
> +
> + topo = cpu_topology__new();
> + if (!topo)
> + return -EINVAL;
> +
> + ret = record__init_thread_masks_spec(rec, cpus, topo->thread_siblings,
> + topo->thread_siblings, topo->thread_sib);
> + cpu_topology__delete(topo);
> +
> + return ret;
> +}
> +
> +static int record__init_thread_socket_masks(struct record *rec, struct perf_cpu_map *cpus)
> +{
> + int ret;
> + struct cpu_topology *topo;
> +
> + topo = cpu_topology__new();
> + if (!topo)
> + return -EINVAL;
> +
> + ret = record__init_thread_masks_spec(rec, cpus, topo->core_siblings,
> + topo->core_siblings, topo->core_sib);
> + cpu_topology__delete(topo);
> +
> + return ret;
> +}
> +
> +static int record__init_thread_numa_masks(struct record *rec, struct perf_cpu_map *cpus)
> +{
> + u32 s;
> + int ret;
> + char **spec;
> + struct numa_topology *topo;
> +
> + topo = numa_topology__new();
> + if (!topo)
> + return -EINVAL;
> + spec = zalloc(topo->nr * sizeof(char *));
> + if (!spec)
> + return -ENOMEM;

Will leak topo.

> + for (s = 0; s < topo->nr; s++)
> + spec[s] = topo->nodes[s].cpus;
> +
> + ret = record__init_thread_masks_spec(rec, cpus, spec, spec, topo->nr);
> +
> + zfree(&spec);
> +
> + numa_topology__delete(topo);
> +
> + return ret;
> +}
> +
> +static int record__init_thread_user_masks(struct record *rec, struct perf_cpu_map *cpus)
> +{
> + int t, ret;
> + u32 s, nr_spec = 0;
> + char **maps_spec = NULL, **affinity_spec = NULL;
> + char *spec, *spec_ptr, *user_spec, *mask, *mask_ptr;
> +
> + for (t = 0, user_spec = (char *)rec->opts.threads_user_spec; ;t++, user_spec = NULL) {
> + spec = strtok_r(user_spec, ":", &spec_ptr);
> + if (spec == NULL)
> + break;
> + pr_debug(" spec[%d]: %s\n", t, spec);
> + mask = strtok_r(spec, "/", &mask_ptr);
> + if (mask == NULL)
> + break;
> + pr_debug(" maps mask: %s\n", mask);
> + maps_spec = realloc(maps_spec, (nr_spec + 1) * sizeof(char *));
> + if (!maps_spec) {
> + pr_err("Failed to realloc maps_spec\n");
> + return -ENOMEM;

Likewise, you can use a temp variable and bail out to free all
existing specs.

> + }
> + maps_spec[nr_spec] = strdup(mask);
> + mask = strtok_r(NULL, "/", &mask_ptr);
> + if (mask == NULL)
> + break;
> + pr_debug(" affinity mask: %s\n", mask);
> + affinity_spec = realloc(affinity_spec, (nr_spec + 1) * sizeof(char *));
> + if (!maps_spec) {
> + pr_err("Failed to realloc affinity_spec\n");
> + return -ENOMEM;

Ditto.

Thanks,
Namhyung

> + }
> + affinity_spec[nr_spec] = strdup(mask);
> + nr_spec++;
> + }
> +
> + ret = record__init_thread_masks_spec(rec, cpus, maps_spec, affinity_spec, nr_spec);
> +
> + for (s = 0; s < nr_spec; s++) {
> + free(maps_spec[s]);
> + free(affinity_spec[s]);
> + }
> + free(affinity_spec);
> + free(maps_spec);
> +
> + return ret;
> +}
> +
> static int record__init_thread_default_masks(struct record *rec, struct perf_cpu_map *cpus)
> {
> int ret;
> @@ -3133,9 +3410,33 @@ static int record__init_thread_default_masks(struct record *rec, struct perf_cpu
>
> static int record__init_thread_masks(struct record *rec)
> {
> + int ret = 0;
> struct perf_cpu_map *cpus = rec->evlist->core.cpus;
>
> - return record__init_thread_default_masks(rec, cpus);
> + if (!record__threads_enabled(rec))
> + return record__init_thread_default_masks(rec, cpus);
> +
> + switch (rec->opts.threads_spec) {
> + case THREAD_SPEC__CPU:
> + ret = record__init_thread_cpu_masks(rec, cpus);
> + break;
> + case THREAD_SPEC__CORE:
> + ret = record__init_thread_core_masks(rec, cpus);
> + break;
> + case THREAD_SPEC__SOCKET:
> + ret = record__init_thread_socket_masks(rec, cpus);
> + break;
> + case THREAD_SPEC__NUMA:
> + ret = record__init_thread_numa_masks(rec, cpus);
> + break;
> + case THREAD_SPEC__USER:
> + ret = record__init_thread_user_masks(rec, cpus);
> + break;
> + default:
> + break;
> + }
> +
> + return ret;
> }
>
> static int record__fini_thread_masks(struct record *rec)
> @@ -3361,7 +3662,10 @@ int cmd_record(int argc, const char **argv)
>
> err = record__init_thread_masks(rec);
> if (err) {
> - pr_err("record__init_thread_masks failed, error %d\n", err);
> + if (err > 0)
> + pr_err("ERROR: parallel data streaming masks (--threads) intersect.\n");
> + else
> + pr_err("record__init_thread_masks failed, error %d\n", err);
> goto out;
> }
>
> diff --git a/tools/perf/util/record.h b/tools/perf/util/record.h
> index 9c13a39cc58f..7f64ff5da2b2 100644
> --- a/tools/perf/util/record.h
> +++ b/tools/perf/util/record.h
> @@ -75,6 +75,7 @@ struct record_opts {
> int ctl_fd_ack;
> bool ctl_fd_close;
> int threads_spec;
> + const char *threads_user_spec;
> };
>
> extern const char * const *record_usage;
> --
> 2.24.1
>
>

Next message: Greg Kroah-Hartman: "[PATCH 5.4 07/17] net/mlx5: Use async EQ setup cleanup helpers for multiple EQs"
Previous message: Greg Kroah-Hartman: "[PATCH 5.4 09/17] net/mlx5: Fix a race when moving command interface to events mode"
In reply to: Alexey Budankov: "[PATCH v3 08/12] perf record: introduce --threads=<spec> command line option"
Next in thread: Alexey Budankov: "[PATCH v3 09/12] perf record: document parallel data streaming mode"
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