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, 18 insertions, 19 deletions

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 949167efa1ed..706f00196b87 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -12,6 +12,7 @@
 
 #include "perf.h"
 
+#include "util/build-id.h"
 #include "util/util.h"
 #include "util/parse-options.h"
 #include "util/parse-events.h"
@@ -65,6 +66,7 @@ static int			nr_poll				=      0;
 static int			nr_cpu				=      0;
 
 static int			file_new			=      1;
+static off_t			post_processing_offset;
 
 static struct perf_session	*session;
 
@@ -114,26 +116,10 @@ static void write_output(void *buf, size_t size)
 	}
 }
 
-static void write_event(event_t *buf, size_t size)
-{
-	/*
-	* Add it to the list of DSOs, so that when we finish this
-	 * record session we can pick the available build-ids.
-	 */
-	if (buf->header.type == PERF_RECORD_MMAP) {
-		struct list_head *head = &dsos__user;
-		if (buf->mmap.header.misc == 1)
-			head = &dsos__kernel;
-		__dsos__findnew(head, buf->mmap.filename);
-	}
-
-	write_output(buf, size);
-}
-
 static int process_synthesized_event(event_t *event,
 				     struct perf_session *self __used)
 {
-	write_event(event, event->header.size);
+	write_output(event, event->header.size);
 	return 0;
 }
 
@@ -185,14 +171,14 @@ static void mmap_read(struct mmap_data *md)
 		size = md->mask + 1 - (old & md->mask);
 		old += size;
 
-		write_event(buf, size);
+		write_output(buf, size);
 	}
 
 	buf = &data[old & md->mask];
 	size = head - old;
 	old += size;
 
-	write_event(buf, size);
+	write_output(buf, size);
 
 	md->prev = old;
 	mmap_write_tail(md, old);
@@ -402,10 +388,21 @@ static void open_counters(int cpu, pid_t pid)
 	nr_cpu++;
 }
 
+static int process_buildids(void)
+{
+	u64 size = lseek(output, 0, SEEK_CUR);
+
+	session->fd = output;
+	return __perf_session__process_events(session, post_processing_offset,
+					      size - post_processing_offset,
+					      size, &build_id__mark_dso_hit_ops);
+}
+
 static void atexit_header(void)
 {
 	session->header.data_size += bytes_written;
 
+	process_buildids();
 	perf_header__write(&session->header, output, true);
 }
 
@@ -558,6 +555,8 @@ static int __cmd_record(int argc, const char **argv)
 			return err;
 	}
 
+	post_processing_offset = lseek(output, 0, SEEK_CUR);
+
 	err = event__synthesize_kernel_mmap(process_synthesized_event,
 					    session, "_text");
 	if (err < 0) {