perf trace: Write to stderr by default

milianw · acmel · commit 007d66a0bd43 · 2015-08-05T16:52:23.000-03:00
Without this patch, it is cumbersome to read the trace output but ignoring the normal, potentially verbose, output of the debuggee. One common example is doing something like the following: perf trace -s find /tmp > /dev/null Without this patch, the trace summary will be lost. Now, it will still be printed at the end. This behavior is also applied by strace. Cc: Milian Wolff <milian.wolff@kdab.com> Cc: David Ahern <dsahern@gmail.com> Link: http://lkml.kernel.org/n/tip-tqnks6y2cnvm5f9g2dsfr7zl@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
@@ -2965,7 +2965,7 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
 			.mmap_pages    = UINT_MAX,
 			.proc_map_timeout  = 500,
 		},
-		.output = stdout,
+		.output = stderr,
 		.show_comm = true,
 		.trace_syscalls = true,
 	};
