[PATCH 25/52] perf session: Add perf_session__peek_event()

Adrian Hunter
2014-07-22T13:20:48Z

Add a function to peek at other events in the
event stream.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
tools/perf/util/session.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++
tools/perf/util/session.h | 5 +++++
2 files changed, 60 insertions(+)

diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 433884c..ca3cd1f 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1089,6 +1089,61 @@ static void event_swap(union perf_event *event, bool sample_id_all)
swap(event, sample_id_all);
}

+int perf_session__peek_event(struct perf_session *session, off_t file_offset,
+ void *buf, size_t buf_sz,
+ union perf_event **event_ptr,
+ struct perf_sample *sample)
+{
+ union perf_event *event;
+ size_t hdr_sz, rest;
+ int fd;
+
+ if (session->one_mmap && !session->header.needs_swap) {
+ event = file_offset - session->one_mmap_offset +
+ session->one_mmap_addr;
+ goto out_parse_sample;
+ }
+
+ if (perf_data_file__is_pipe(session->file))
+ return -1;
+
+ fd = perf_data_file__fd(session->file);
+ hdr_sz = sizeof(struct perf_event_header);
+
+ if (buf_sz < hdr_sz)
+ return -1;
+
+ if (lseek(fd, file_offset, SEEK_SET) == (off_t)-1 ||
+ readn(fd, &buf, hdr_sz) != (ssize_t)hdr_sz)
+ return -1;
+
+ event = (union perf_event *)buf;
+
+ if (session->header.needs_swap)
+ perf_event_header__bswap(&event->header);
+
+ if (event->header.size < hdr_sz)
+ return -1;
+
+ rest = event->header.size - hdr_sz;
+
+ if (readn(fd, &buf, rest) != (ssize_t)rest)
+ return -1;
+
+ if (session->header.needs_swap)
+ event_swap(event, perf_evlist__sample_id_all(session->evlist));
+
+out_parse_sample:
+
+ if (sample && event->header.type < PERF_RECORD_USER_TYPE_START &&
+ perf_evlist__parse_sample(session->evlist, event, sample))
+ return -1;
+
+ *event_ptr = event;
+
+ return 0;
+}
+
static s64 perf_session__process_event(struct perf_session *session,
union perf_event *event,
struct perf_tool *tool,
diff --git a/tools/perf/util/session.h b/tools/perf/util/session.h
index 86f1bb4..e4ea0cf5 100644
--- a/tools/perf/util/session.h
+++ b/tools/perf/util/session.h
@@ -58,6 +58,11 @@ void perf_session__delete(struct perf_session *session);

void perf_event_header__bswap(struct perf_event_header *hdr);

+int perf_session__peek_event(struct perf_session *session, off_t file_offset,
+ void *buf, size_t buf_sz,
+ union perf_event **event_ptr,
+ struct perf_sample *sample);
+
int __perf_session__process_events(struct perf_session *session,
u64 data_offset, u64 data_size, u64 size,
struct perf_tool *tool);
--
1.8.3.2