perf report: add more debugging

Add the offset of the file we are analyzing, and the size of the record.

In case of problems it's easier to see where the parser lost track.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: John Kacur <jkacur@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Documentation/perf_counter/builtin-report.c

@@ -645,7 +645,7 @@ static int __cmd_report(void)
 	char *buf;
 	event_t *event;
 	int ret, rc = EXIT_FAILURE;
-	unsigned long total = 0, total_mmap = 0, total_comm = 0, total_unknown;
+	unsigned long total = 0, total_mmap = 0, total_comm = 0, total_unknown = 0;
 
 	input = open(input_name, O_RDONLY);
 	if (input < 0) {
@@ -699,8 +699,6 @@ more:
 		goto done;
 	}
 
-	head += event->header.size;
-
 	if (event->header.misc & PERF_EVENT_MISC_OVERFLOW) {
 		char level;
 		int show = 0;
@@ -709,7 +707,9 @@ more:
 		uint64_t ip = event->ip.ip;
 
 		if (dump_trace) {
-			fprintf(stderr, "PERF_EVENT (IP, %d): %d: %p\n",
+			fprintf(stderr, "%p [%p]: PERF_EVENT (IP, %d): %d: %p\n",
+				(void *)(offset + head),
+				(void *)(long)(event->header.size),
 				event->header.misc,
 				event->ip.pid,
 				(void *)event->ip.ip);
@@ -753,7 +753,9 @@ more:
 		struct map *map = map__new(&event->mmap);
 
 		if (dump_trace) {
-			fprintf(stderr, "PERF_EVENT_MMAP: [%p(%p) @ %p]: %s\n",
+			fprintf(stderr, "%p [%p]: PERF_EVENT_MMAP: [%p(%p) @ %p]: %s\n",
+				(void *)(offset + head),
+				(void *)(long)(event->header.size),
 				(void *)event->mmap.start,
 				(void *)event->mmap.len,
 				(void *)event->mmap.pgoff,
@@ -771,7 +773,9 @@ more:
 		struct thread *thread = threads__findnew(event->comm.pid);
 
 		if (dump_trace) {
-			fprintf(stderr, "PERF_EVENT_COMM: %s:%d\n",
+			fprintf(stderr, "%p [%p]: PERF_EVENT_COMM: %s:%d\n",
+				(void *)(offset + head),
+				(void *)(long)(event->header.size),
 				event->comm.comm, event->comm.pid);
 		}
 		if (thread == NULL ||
@@ -783,12 +787,16 @@ more:
 		break;
 	}
 	default: {
-		fprintf(stderr, "skipping unknown header type: %d\n",
+		fprintf(stderr, "%p [%p]: skipping unknown header type: %d\n",
+			(void *)(offset + head),
+			(void *)(long)(event->header.size),
 			event->header.type);
 		total_unknown++;
 	}
 	}
 
+	head += event->header.size;
+
 	if (offset + head < stat.st_size)
 		goto more;