perf record: Stop intercepting events, use postprocessing to get build-ids

We want to stream events as fast as possible to perf.data, and
also in the future we want to have splice working, when no
interception will be possible.

Using build_id__mark_dso_hit_ops to create the list of DSOs that
back MMAPs we also optimize disk usage in the build-id cache by
only caching DSOs that had hits.

Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1265223128-11786-6-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 5 insertions, 2 deletions

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index ed3efd728b41..d5facd5ab1f7 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -205,8 +205,11 @@ static int __dsos__write_buildid_table(struct list_head *head, u16 misc, int fd)
         dsos__for_each_with_build_id(pos, head) {
                 int err;
                 struct build_id_event b;
-                size_t len = pos->long_name_len + 1;
+                size_t len;
 
+                if (!pos->hit)
+                        continue;
+                len = pos->long_name_len + 1;
                 len = ALIGN(len, NAME_ALIGN);
                 memset(&b, 0, sizeof(b));
                 memcpy(&b.build_id, pos->build_id, sizeof(pos->build_id));
@@ -371,7 +374,7 @@ static int perf_header__adds_write(struct perf_header *self, int fd)
         u64 sec_start;
         int idx = 0, err;
 
-        if (dsos__read_build_ids())
+        if (dsos__read_build_ids(true))
                 perf_header__set_feat(self, HEADER_BUILD_ID);
 
         nr_sections = bitmap_weight(self->adds_features, HEADER_FEAT_BITS);