[PATCH v4 04/53] perf mmap: Lazily initialize zstd streams

From: Ian Rogers
Date: Thu Nov 02 2023 - 13:58:25 EST

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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.

Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
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)) {
--
2.42.0.869.gea05f2083d-goog

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