[tip:perf/core] perf trace: Write to stderr by default

[tip-bot for Milian Wolff <tipbot@zytor.com>]

Commit-ID:  007d66a0bd43d886eb3e4aceaf1a96b8743ccaff
Gitweb:     http://git.kernel.org/tip/007d66a0bd43d886eb3e4aceaf1a96b8743ccaff
Author:     Milian Wolff <milian.wolff@kdab.com>
AuthorDate: Wed, 5 Aug 2015 16:52:23 -0300
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Wed, 5 Aug 2015 16:52:23 -0300

perf trace: Write to stderr by default

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>
---
 tools/perf/builtin-trace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 98d423e..a474970 100644
--- 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,
 	};