[PATCH v10 18/24] perf session: Introduce reader_state in reader object

Alexey Bayduraev
2021-07-12T07:12:13Z

We need all the state info about reader in separate object to load data
from multiple files, so we can keep multiple readers at the same time.
Adding struct reader_state and adding all items that need to be kept.

Design and implementation are based on the prototype [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@kernel.org/

Suggested-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
---
tools/perf/util/session.c | 74 +++++++++++++++++++++++----------------
1 file changed, 43 insertions(+), 31 deletions(-)

diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 1cfb5655e092..da39ce4acb5a 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -55,6 +55,17 @@ typedef s64 (*reader_cb_t)(struct perf_session *session,
u64 file_offset,
const char *file_path);

+struct reader_state {
+ char *mmaps[NUM_MMAPS];
+ size_t mmap_size;
+ int mmap_idx;
+ char *mmap_cur;
+ u64 file_pos;
+ u64 file_offset;
+ u64 data_size;
+ u64 head;
+};
+
struct reader {
int fd;
const char *path;
@@ -62,6 +73,7 @@ struct reader {
u64 data_offset;
reader_cb_t process;
bool in_place_update;
+ struct reader_state state;
};

#ifdef HAVE_ZSTD_SUPPORT
@@ -2178,29 +2190,28 @@ static int
reader__process_events(struct reader *rd, struct perf_session *session,
struct ui_progress *prog)
{
- u64 data_size = rd->data_size;
- u64 head, page_offset, file_offset, file_pos, size;
- int err = 0, mmap_prot, mmap_flags, map_idx = 0;
- size_t mmap_size;
- char *buf, *mmaps[NUM_MMAPS];
+ struct reader_state *st = &rd->state;
+ u64 page_offset, size;
+ int err = 0, mmap_prot, mmap_flags;
+ char *buf, **mmaps = st->mmaps;
union perf_event *event;
s64 skip;

page_offset = page_size * (rd->data_offset / page_size);
- file_offset = page_offset;
- head = rd->data_offset - page_offset;
+ st->file_offset = page_offset;
+ st->head = rd->data_offset - page_offset;

- ui_progress__init_size(prog, data_size, "Processing events...");
+ ui_progress__init_size(prog, rd->data_size, "Processing events...");

- data_size += rd->data_offset;
+ st->data_size = rd->data_size + rd->data_offset;

- mmap_size = MMAP_SIZE;
- if (mmap_size > data_size) {
- mmap_size = data_size;
+ st->mmap_size = MMAP_SIZE;
+ if (st->mmap_size > st->data_size) {
+ st->mmap_size = st->data_size;
session->one_mmap = true;
}

- memset(mmaps, 0, sizeof(mmaps));
+ memset(mmaps, 0, sizeof(st->mmaps));

mmap_prot = PROT_READ;
mmap_flags = MAP_SHARED;
@@ -2212,35 +2223,36 @@ reader__process_events(struct reader *rd, struct perf_session *session,
mmap_flags = MAP_PRIVATE;
}
remap:
- buf = mmap(NULL, mmap_size, mmap_prot, mmap_flags, rd->fd,
- file_offset);
+ buf = mmap(NULL, st->mmap_size, mmap_prot, mmap_flags, rd->fd,
+ st->file_offset);
if (buf == MAP_FAILED) {
pr_err("failed to mmap file\n");
err = -errno;
goto out;
}
- mmaps[map_idx] = buf;
- map_idx = (map_idx + 1) & (ARRAY_SIZE(mmaps) - 1);
- file_pos = file_offset + head;
+ mmaps[st->mmap_idx] = st->mmap_cur = buf;
+ st->mmap_idx = (st->mmap_idx + 1) & (ARRAY_SIZE(st->mmaps) - 1);
+ st->file_pos = st->file_offset + st->head;
if (session->one_mmap) {
session->one_mmap_addr = buf;
- session->one_mmap_offset = file_offset;
+ session->one_mmap_offset = st->file_offset;
}

more:
- event = fetch_mmaped_event(head, mmap_size, buf, session->header.needs_swap);
+ event = fetch_mmaped_event(st->head, st->mmap_size, st->mmap_cur,
+ session->header.needs_swap);
if (IS_ERR(event))
return PTR_ERR(event);

if (!event) {
- if (mmaps[map_idx]) {
- munmap(mmaps[map_idx], mmap_size);
- mmaps[map_idx] = NULL;
+ if (mmaps[st->mmap_idx]) {
+ munmap(mmaps[st->mmap_idx], st->mmap_size);
+ mmaps[st->mmap_idx] = NULL;
}

- page_offset = page_size * (head / page_size);
- file_offset += page_offset;
- head -= page_offset;
+ page_offset = page_size * (st->head / page_size);
+ st->file_offset += page_offset;
+ st->head -= page_offset;
goto remap;
}

@@ -2249,9 +2261,9 @@ reader__process_events(struct reader *rd, struct perf_session *session,
skip = -EINVAL;

if (size < sizeof(struct perf_event_header) ||
- (skip = rd->process(session, event, file_pos, rd->path)) < 0) {
+ (skip = rd->process(session, event, st->file_pos, rd->path)) < 0) {
pr_err("%#" PRIx64 " [%s] [%#x]: failed to process type: %d [%s]\n",
- file_offset + head, rd->path, event->header.size,
+ st->file_offset + st->head, rd->path, event->header.size,
event->header.type, strerror(-skip));
err = skip;
goto out;
@@ -2260,8 +2272,8 @@ reader__process_events(struct reader *rd, struct perf_session *session,
if (skip)
size += skip;

- head += size;
- file_pos += size;
+ st->head += size;
+ st->file_pos += size;

err = __perf_session__process_decomp_events(session);
if (err)
@@ -2272,7 +2284,7 @@ reader__process_events(struct reader *rd, struct perf_session *session,
if (session_done())
goto out;

- if (file_pos < data_size)
+ if (st->file_pos < st->data_size)
goto more;

out:
--
2.19.0