linux-kernel - [PATCH 11/21] perf trace: Hide sys_exit messages about syscall id = -1

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Date:	Wed, 28 Aug 2013 11:59:27 -0300
From:	Arnaldo Carvalho de Melo <acme@...radead.org>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	linux-kernel@...r.kernel.org,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	David Ahern <dsahern@...il.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Mike Galbraith <efault@....de>,
	Paul Mackerras <paulus@...ba.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Stephane Eranian <eranian@...gle.com>
Subject: [PATCH 11/21] perf trace: Hide sys_exit messages about syscall id = -1

From: Arnaldo Carvalho de Melo <acme@...hat.com>

That was reproduced via ftrace as described in this cset comment log,
need to investigate further.

Cc: Adrian Hunter <adrian.hunter@...el.com>
Cc: David Ahern <dsahern@...il.com>
Cc: Frederic Weisbecker <fweisbec@...il.com>
Cc: Mike Galbraith <efault@....de>
Cc: Paul Mackerras <paulus@...ba.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Stephane Eranian <eranian@...gle.com>
Link: http://lkml.kernel.org/n/tip-n1i3m0vo6mgq3ddjj95sls2s@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 tools/perf/builtin-trace.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index c907e7e..c3caabb 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -298,7 +298,22 @@ static struct syscall *trace__syscall_info(struct trace *trace,
 	int id = perf_evsel__intval(evsel, sample, "id");
 
 	if (id < 0) {
-		fprintf(trace->output, "Invalid syscall %d id, skipping...\n", id);
+
+		/*
+		 * XXX: Noticed on x86_64, reproduced as far back as 3.0.36, haven't tried
+		 * before that, leaving at a higher verbosity level till that is
+		 * explained. Reproduced with plain ftrace with:
+		 *
+		 * echo 1 > /t/events/raw_syscalls/sys_exit/enable
+		 * grep "NR -1 " /t/trace_pipe
+		 *
+		 * After generating some load on the machine.
+ 		 */
+		if (verbose > 1) {
+			static u64 n;
+			fprintf(trace->output, "Invalid syscall %d id, skipping (%s, %" PRIu64 ") ...\n",
+				id, perf_evsel__name(evsel), ++n);
+		}
 		return NULL;
 	}
 
-- 
1.8.1.4

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