[PATCH 2/4] perf tools: Warn while running perf trace without sample

[Frederic Weisbecker <fweisbec@gmail.com>]

When a user runs perf trace using an input with logged counters
without PERF_SAMPLE_RAW attribute, warn by giving a nice tip.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
---
 tools/perf/builtin-trace.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index b160a9f..88eef71 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -184,6 +184,10 @@ static int __cmd_trace(void)
 	header = perf_header__read(input);
 	sample_type = perf_header__sample_type(header);
 
+	if (!(sample_type & PERF_SAMPLE_RAW))
+		die("No trace sample to read. Did you call perf record "
+		    "without -R?");
+
 	if (load_kernel() < 0) {
 		perror("failed to load kernel symbols");
 		return EXIT_FAILURE;
-- 
1.6.2.3