diff options
| -rw-r--r-- | tools/perf/util/evlist.c | 35 | ||||
| -rw-r--r-- | tools/perf/util/evlist.h | 1 | ||||
| -rw-r--r-- | tools/perf/util/evsel.c | 1 |
3 files changed, 22 insertions, 15 deletions
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index df0610e9c61b..b498eecbe850 100644 --- a/tools/perf/util/evlist.c +++ b/tools/perf/util/evlist.c @@ -116,24 +116,25 @@ event_t *perf_evlist__read_on_cpu(struct perf_evlist *evlist, int cpu) unsigned int old = md->prev; unsigned char *data = md->base + page_size; event_t *event = NULL; - int diff; - - /* - * If we're further behind than half the buffer, there's a chance - * the writer will bite our tail and mess up the samples under us. - * - * If we somehow ended up ahead of the head, we got messed up. - * - * In either case, truncate and restart at head. - */ - diff = head - old; - if (diff > md->mask / 2 || diff < 0) { - fprintf(stderr, "WARNING: failed to keep up with mmap data.\n"); + if (evlist->overwrite) { /* - * head points to a known good entry, start there. + * If we're further behind than half the buffer, there's a chance + * the writer will bite our tail and mess up the samples under us. + * + * If we somehow ended up ahead of the head, we got messed up. + * + * In either case, truncate and restart at head. */ - old = head; + int diff = head - old; + if (diff > md->mask / 2 || diff < 0) { + fprintf(stderr, "WARNING: failed to keep up with mmap data.\n"); + + /* + * head points to a known good entry, start there. + */ + old = head; + } } if (old != head) { @@ -166,5 +167,9 @@ event_t *perf_evlist__read_on_cpu(struct perf_evlist *evlist, int cpu) } md->prev = old; + + if (!evlist->overwrite) + perf_mmap__write_tail(md, old); + return event; } diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h index acbe48eac608..2706ae40c8b3 100644 --- a/tools/perf/util/evlist.h +++ b/tools/perf/util/evlist.h @@ -16,6 +16,7 @@ struct perf_evlist { int nr_entries; int nr_fds; int mmap_len; + bool overwrite; event_t event_copy; struct perf_mmap *mmap; struct pollfd *pollfd; diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index 76ab553637d6..f98b3e585039 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -327,6 +327,7 @@ int perf_evlist__mmap(struct perf_evlist *evlist, struct cpu_map *cpus, perf_evlist__alloc_pollfd(evlist, cpus->nr, threads->nr) < 0) return -ENOMEM; + evlist->overwrite = overwrite; evlist->mmap_len = (pages + 1) * page_size; first_evsel = list_entry(evlist->entries.next, struct perf_evsel, node); |