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From:   Namhyung Kim <namhyung@kernel.org>
Date:   Wed, 29 Nov 2023 17:28:56 -0800
Message-ID: <CAM9d7cg8TRiBVQCO_zKjb+D==06o5a=CH_gF_wDW7_PJtZfHKw@mail.gmail.com>
Subject: Re: [PATCH v5 03/50] perf mmap: Lazily initialize zstd streams
To:     Ian Rogers <irogers@google.com>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Nick Terrell <terrelln@fb.com>,
        Kan Liang <kan.liang@linux.intel.com>,
        Andi Kleen <ak@linux.intel.com>,
        Kajol Jain <kjain@linux.ibm.com>,
        Athira Rajeev <atrajeev@linux.vnet.ibm.com>,
        Huacai Chen <chenhuacai@kernel.org>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Vincent Whitchurch <vincent.whitchurch@axis.com>,
        "Steinar H. Gunderson" <sesse@google.com>,
        Liam Howlett <liam.howlett@oracle.com>,
        Miguel Ojeda <ojeda@kernel.org>,
        Colin Ian King <colin.i.king@gmail.com>,
        Dmitrii Dolgov <9erthalion6@gmail.com>,
        Yang Jihong <yangjihong1@huawei.com>,
        Ming Wang <wangming01@loongson.cn>,
        James Clark <james.clark@arm.com>,
        K Prateek Nayak <kprateek.nayak@amd.com>,
        Sean Christopherson <seanjc@google.com>,
        Leo Yan <leo.yan@linaro.org>,
        Ravi Bangoria <ravi.bangoria@amd.com>,
        German Gomez <german.gomez@arm.com>,
        Changbin Du <changbin.du@huawei.com>,
        Paolo Bonzini <pbonzini@redhat.com>, Li Dong <lidong@vivo.com>,
        Sandipan Das <sandipan.das@amd.com>,
        liuwenyu <liuwenyu7@huawei.com>, linux-kernel@vger.kernel.org,
        linux-perf-users@vger.kernel.org,
        Guilherme Amadio <amadio@gentoo.org>
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On Mon, Nov 27, 2023 at 2:09 PM Ian Rogers <irogers@google.com> wrote:
>
> Zstd streams create dictionaries that can require significant RAM,
> especially when there is one per-CPU. Tools like perf record won't use
> the streams without the -z option, and so the creation of the streams
> is pure overhead. Switch to creating the streams on first use.

I think this one is already in the perf-tools-next.

Thanks,
Namhyung

>
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
>  tools/perf/builtin-record.c | 26 ++++++++++-----
>  tools/perf/util/compress.h  |  6 ++--
>  tools/perf/util/mmap.c      |  5 ++-
>  tools/perf/util/mmap.h      |  1 -
>  tools/perf/util/zstd.c      | 63 +++++++++++++++++++------------------
>  5 files changed, 58 insertions(+), 43 deletions(-)
>
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index 8ec818568662..9b4f3805ca92 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -270,7 +270,7 @@ static int record__write(struct record *rec, struct mmap *map __maybe_unused,
>
>  static int record__aio_enabled(struct record *rec);
>  static int record__comp_enabled(struct record *rec);
> -static size_t zstd_compress(struct perf_session *session, struct mmap *map,
> +static ssize_t zstd_compress(struct perf_session *session, struct mmap *map,
>                             void *dst, size_t dst_size, void *src, size_t src_size);
>
>  #ifdef HAVE_AIO_SUPPORT
> @@ -405,9 +405,13 @@ static int record__aio_pushfn(struct mmap *map, void *to, void *buf, size_t size
>          */
>
>         if (record__comp_enabled(aio->rec)) {
> -               size = zstd_compress(aio->rec->session, NULL, aio->data + aio->size,
> -                                    mmap__mmap_len(map) - aio->size,
> -                                    buf, size);
> +               ssize_t compressed = zstd_compress(aio->rec->session, NULL, aio->data + aio->size,
> +                                                  mmap__mmap_len(map) - aio->size,
> +                                                  buf, size);
> +               if (compressed < 0)
> +                       return (int)compressed;
> +
> +               size = compressed;
>         } else {
>                 memcpy(aio->data + aio->size, buf, size);
>         }
> @@ -633,7 +637,13 @@ static int record__pushfn(struct mmap *map, void *to, void *bf, size_t size)
>         struct record *rec = to;
>
>         if (record__comp_enabled(rec)) {
> -               size = zstd_compress(rec->session, map, map->data, mmap__mmap_len(map), bf, size);
> +               ssize_t compressed = zstd_compress(rec->session, map, map->data,
> +                                                  mmap__mmap_len(map), bf, size);
> +
> +               if (compressed < 0)
> +                       return (int)compressed;
> +
> +               size = compressed;
>                 bf   = map->data;
>         }
>
> @@ -1527,10 +1537,10 @@ static size_t process_comp_header(void *record, size_t increment)
>         return size;
>  }
>
> -static size_t zstd_compress(struct perf_session *session, struct mmap *map,
> +static ssize_t zstd_compress(struct perf_session *session, struct mmap *map,
>                             void *dst, size_t dst_size, void *src, size_t src_size)
>  {
> -       size_t compressed;
> +       ssize_t compressed;
>         size_t max_record_size = PERF_SAMPLE_MAX_SIZE - sizeof(struct perf_record_compressed) - 1;
>         struct zstd_data *zstd_data = &session->zstd_data;
>
> @@ -1539,6 +1549,8 @@ static size_t zstd_compress(struct perf_session *session, struct mmap *map,
>
>         compressed = zstd_compress_stream_to_records(zstd_data, dst, dst_size, src, src_size,
>                                                      max_record_size, process_comp_header);
> +       if (compressed < 0)
> +               return compressed;
>
>         if (map && map->file) {
>                 thread->bytes_transferred += src_size;
> diff --git a/tools/perf/util/compress.h b/tools/perf/util/compress.h
> index 0cd3369af2a4..9eb6eb5bf038 100644
> --- a/tools/perf/util/compress.h
> +++ b/tools/perf/util/compress.h
> @@ -3,6 +3,7 @@
>  #define PERF_COMPRESS_H
>
>  #include <stdbool.h>
> +#include <stdlib.h>
>  #ifdef HAVE_ZSTD_SUPPORT
>  #include <zstd.h>
>  #endif
> @@ -21,6 +22,7 @@ struct zstd_data {
>  #ifdef HAVE_ZSTD_SUPPORT
>         ZSTD_CStream    *cstream;
>         ZSTD_DStream    *dstream;
> +       int comp_level;
>  #endif
>  };
>
> @@ -29,7 +31,7 @@ struct zstd_data {
>  int zstd_init(struct zstd_data *data, int level);
>  int zstd_fini(struct zstd_data *data);
>
> -size_t zstd_compress_stream_to_records(struct zstd_data *data, void *dst, size_t dst_size,
> +ssize_t zstd_compress_stream_to_records(struct zstd_data *data, void *dst, size_t dst_size,
>                                        void *src, size_t src_size, size_t max_record_size,
>                                        size_t process_header(void *record, size_t increment));
>
> @@ -48,7 +50,7 @@ static inline int zstd_fini(struct zstd_data *data __maybe_unused)
>  }
>
>  static inline
> -size_t zstd_compress_stream_to_records(struct zstd_data *data __maybe_unused,
> +ssize_t zstd_compress_stream_to_records(struct zstd_data *data __maybe_unused,
>                                        void *dst __maybe_unused, size_t dst_size __maybe_unused,
>                                        void *src __maybe_unused, size_t src_size __maybe_unused,
>                                        size_t max_record_size __maybe_unused,
> diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
> index 49093b21ee2d..122ee198a86e 100644
> --- a/tools/perf/util/mmap.c
> +++ b/tools/perf/util/mmap.c
> @@ -295,15 +295,14 @@ int mmap__mmap(struct mmap *map, struct mmap_params *mp, int fd, struct perf_cpu
>
>         map->core.flush = mp->flush;
>
> -       map->comp_level = mp->comp_level;
>  #ifndef PYTHON_PERF
> -       if (zstd_init(&map->zstd_data, map->comp_level)) {
> +       if (zstd_init(&map->zstd_data, mp->comp_level)) {
>                 pr_debug2("failed to init mmap compressor, error %d\n", errno);
>                 return -1;
>         }
>  #endif
>
> -       if (map->comp_level && !perf_mmap__aio_enabled(map)) {
> +       if (mp->comp_level && !perf_mmap__aio_enabled(map)) {
>                 map->data = mmap(NULL, mmap__mmap_len(map), PROT_READ|PROT_WRITE,
>                                  MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
>                 if (map->data == MAP_FAILED) {
> diff --git a/tools/perf/util/mmap.h b/tools/perf/util/mmap.h
> index f944c3cd5efa..0df6e1621c7e 100644
> --- a/tools/perf/util/mmap.h
> +++ b/tools/perf/util/mmap.h
> @@ -39,7 +39,6 @@ struct mmap {
>  #endif
>         struct mmap_cpu_mask    affinity_mask;
>         void            *data;
> -       int             comp_level;
>         struct perf_data_file *file;
>         struct zstd_data      zstd_data;
>  };
> diff --git a/tools/perf/util/zstd.c b/tools/perf/util/zstd.c
> index 48dd2b018c47..57027e0ac7b6 100644
> --- a/tools/perf/util/zstd.c
> +++ b/tools/perf/util/zstd.c
> @@ -7,35 +7,9 @@
>
>  int zstd_init(struct zstd_data *data, int level)
>  {
> -       size_t ret;
> -
> -       data->dstream = ZSTD_createDStream();
> -       if (data->dstream == NULL) {
> -               pr_err("Couldn't create decompression stream.\n");
> -               return -1;
> -       }
> -
> -       ret = ZSTD_initDStream(data->dstream);
> -       if (ZSTD_isError(ret)) {
> -               pr_err("Failed to initialize decompression stream: %s\n", ZSTD_getErrorName(ret));
> -               return -1;
> -       }
> -
> -       if (!level)
> -               return 0;
> -
> -       data->cstream = ZSTD_createCStream();
> -       if (data->cstream == NULL) {
> -               pr_err("Couldn't create compression stream.\n");
> -               return -1;
> -       }
> -
> -       ret = ZSTD_initCStream(data->cstream, level);
> -       if (ZSTD_isError(ret)) {
> -               pr_err("Failed to initialize compression stream: %s\n", ZSTD_getErrorName(ret));
> -               return -1;
> -       }
> -
> +       data->comp_level = level;
> +       data->dstream = NULL;
> +       data->cstream = NULL;
>         return 0;
>  }
>
> @@ -54,7 +28,7 @@ int zstd_fini(struct zstd_data *data)
>         return 0;
>  }
>
> -size_t zstd_compress_stream_to_records(struct zstd_data *data, void *dst, size_t dst_size,
> +ssize_t zstd_compress_stream_to_records(struct zstd_data *data, void *dst, size_t dst_size,
>                                        void *src, size_t src_size, size_t max_record_size,
>                                        size_t process_header(void *record, size_t increment))
>  {
> @@ -63,6 +37,21 @@ size_t zstd_compress_stream_to_records(struct zstd_data *data, void *dst, size_t
>         ZSTD_outBuffer output;
>         void *record;
>
> +       if (!data->cstream) {
> +               data->cstream = ZSTD_createCStream();
> +               if (data->cstream == NULL) {
> +                       pr_err("Couldn't create compression stream.\n");
> +                       return -1;
> +               }
> +
> +               ret = ZSTD_initCStream(data->cstream, data->comp_level);
> +               if (ZSTD_isError(ret)) {
> +                       pr_err("Failed to initialize compression stream: %s\n",
> +                               ZSTD_getErrorName(ret));
> +                       return -1;
> +               }
> +       }
> +
>         while (input.pos < input.size) {
>                 record = dst;
>                 size = process_header(record, 0);
> @@ -96,6 +85,20 @@ size_t zstd_decompress_stream(struct zstd_data *data, void *src, size_t src_size
>         ZSTD_inBuffer input = { src, src_size, 0 };
>         ZSTD_outBuffer output = { dst, dst_size, 0 };
>
> +       if (!data->dstream) {
> +               data->dstream = ZSTD_createDStream();
> +               if (data->dstream == NULL) {
> +                       pr_err("Couldn't create decompression stream.\n");
> +                       return 0;
> +               }
> +
> +               ret = ZSTD_initDStream(data->dstream);
> +               if (ZSTD_isError(ret)) {
> +                       pr_err("Failed to initialize decompression stream: %s\n",
> +                               ZSTD_getErrorName(ret));
> +                       return 0;
> +               }
> +       }
>         while (input.pos < input.size) {
>                 ret = ZSTD_decompressStream(data->dstream, &output, &input);
>                 if (ZSTD_isError(ret)) {
> --
> 2.43.0.rc1.413.gea7ed67945-goog
>