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Message-ID: <YguaF9kmFyoZ1ZhC@krava>
Date: Tue, 15 Feb 2022 13:18:31 +0100
From: Jiri Olsa <olsajiri@...il.com>
To: "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@...il.com>
Cc: acme@...nel.org, jolsa@...hat.com,
linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] libperf: Add API for allocating new thread map
On Thu, Feb 10, 2022 at 10:52:25AM +0200, Tzvetomir Stoyanov (VMware) wrote:
> The existing API perf_thread_map__new_dummy() allocates new thread map
> for one thread. I couldn't find a way to reallocate the map with more
> threads, or to allocate a new map for more than one thread. Having
> multiple threads in a thread map is essential for some use cases.
> That's why a new API is proposed, which allocates a new thread map
> for given number of threads:
> perf_thread_map__new()
I'm ok with that, just wondering if we should call it 'perf_thread_map__new_nr'
because we already have perf_cpu_map__new(const char *cpu_list) so
it might be better to keep perf_cpu_map and perf_thread_map in sync
Arnaldo, thoughts on this?
jirka
>
> Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@...il.com>
> ---
> tools/lib/perf/Documentation/libperf.txt | 1 +
> tools/lib/perf/include/perf/threadmap.h | 1 +
> tools/lib/perf/libperf.map | 1 +
> tools/lib/perf/tests/test-threadmap.c | 27 ++++++++++++++++++++++++
> tools/lib/perf/threadmap.c | 15 +++++++++----
> 5 files changed, 41 insertions(+), 4 deletions(-)
>
> diff --git a/tools/lib/perf/Documentation/libperf.txt b/tools/lib/perf/Documentation/libperf.txt
> index 32c5051c24eb..9cbd41c29bff 100644
> --- a/tools/lib/perf/Documentation/libperf.txt
> +++ b/tools/lib/perf/Documentation/libperf.txt
> @@ -62,6 +62,7 @@ SYNOPSIS
> struct perf_thread_map;
>
> struct perf_thread_map *perf_thread_map__new_dummy(void);
> + struct perf_thread_map *perf_thread_map__new(int nr);
>
> void perf_thread_map__set_pid(struct perf_thread_map *map, int thread, pid_t pid);
> char *perf_thread_map__comm(struct perf_thread_map *map, int thread);
> diff --git a/tools/lib/perf/include/perf/threadmap.h b/tools/lib/perf/include/perf/threadmap.h
> index a7c50de8d010..47d433416040 100644
> --- a/tools/lib/perf/include/perf/threadmap.h
> +++ b/tools/lib/perf/include/perf/threadmap.h
> @@ -8,6 +8,7 @@
> struct perf_thread_map;
>
> LIBPERF_API struct perf_thread_map *perf_thread_map__new_dummy(void);
> +LIBPERF_API struct perf_thread_map *perf_thread_map__new(int nr);
>
> LIBPERF_API void perf_thread_map__set_pid(struct perf_thread_map *map, int thread, pid_t pid);
> LIBPERF_API char *perf_thread_map__comm(struct perf_thread_map *map, int thread);
> diff --git a/tools/lib/perf/libperf.map b/tools/lib/perf/libperf.map
> index 93696affda2e..240a2f087b70 100644
> --- a/tools/lib/perf/libperf.map
> +++ b/tools/lib/perf/libperf.map
> @@ -11,6 +11,7 @@ LIBPERF_0.0.1 {
> perf_cpu_map__empty;
> perf_cpu_map__max;
> perf_cpu_map__has;
> + perf_thread_map__new;
> perf_thread_map__new_dummy;
> perf_thread_map__set_pid;
> perf_thread_map__comm;
> diff --git a/tools/lib/perf/tests/test-threadmap.c b/tools/lib/perf/tests/test-threadmap.c
> index 5e2a0291e94c..3388bf36dfc0 100644
> --- a/tools/lib/perf/tests/test-threadmap.c
> +++ b/tools/lib/perf/tests/test-threadmap.c
> @@ -11,9 +11,12 @@ static int libperf_print(enum libperf_print_level level,
> return vfprintf(stderr, fmt, ap);
> }
>
> +#define THREADS_NR 5
> +
> int test_threadmap(int argc, char **argv)
> {
> struct perf_thread_map *threads;
> + int i;
>
> __T_START;
>
> @@ -27,6 +30,30 @@ int test_threadmap(int argc, char **argv)
> perf_thread_map__put(threads);
> perf_thread_map__put(threads);
>
> + threads = perf_thread_map__new(THREADS_NR);
> + if (!threads)
> + tests_failed++;
> +
> + if (perf_thread_map__nr(threads) != THREADS_NR)
> + tests_failed++;
> +
> + for (i = 0; i < THREADS_NR; i++) {
> + if (perf_thread_map__pid(threads, i) != -1)
> + tests_failed++;
> + }
> +
> + for (i = 1; i < THREADS_NR; i++)
> + perf_thread_map__set_pid(threads, i, i * 100);
> +
> + if (perf_thread_map__pid(threads, 0) != -1)
> + tests_failed++;
> +
> + for (i = 1; i < THREADS_NR; i++) {
> + if (perf_thread_map__pid(threads, i) != i * 100)
> + tests_failed++;
> + }
> + perf_thread_map__put(threads);
> +
> __T_END;
> return tests_failed == 0 ? 0 : -1;
> }
> diff --git a/tools/lib/perf/threadmap.c b/tools/lib/perf/threadmap.c
> index e92c368b0a6c..843fe1070cc9 100644
> --- a/tools/lib/perf/threadmap.c
> +++ b/tools/lib/perf/threadmap.c
> @@ -42,18 +42,25 @@ char *perf_thread_map__comm(struct perf_thread_map *map, int thread)
> return map->map[thread].comm;
> }
>
> -struct perf_thread_map *perf_thread_map__new_dummy(void)
> +struct perf_thread_map *perf_thread_map__new(int nr)
> {
> - struct perf_thread_map *threads = thread_map__alloc(1);
> + struct perf_thread_map *threads = thread_map__alloc(nr);
> + int i;
>
> if (threads != NULL) {
> - perf_thread_map__set_pid(threads, 0, -1);
> - threads->nr = 1;
> + for (i = 0; i < nr; i++)
> + perf_thread_map__set_pid(threads, i, -1);
> + threads->nr = nr;
> refcount_set(&threads->refcnt, 1);
> }
> return threads;
> }
>
> +struct perf_thread_map *perf_thread_map__new_dummy(void)
> +{
> + return perf_thread_map__new(1);
> +}
> +
> static void perf_thread_map__delete(struct perf_thread_map *threads)
> {
> if (threads) {
> --
> 2.34.1
>
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