diff --git a/kernel/trace/trace_benchmark.c b/kernel/trace/trace_benchmark.c
index a10adc7..8bd3365 100644
--- a/kernel/trace/trace_benchmark.c
+++ b/kernel/trace/trace_benchmark.c
@@ -33,7 +33,7 @@
 	u64 start;
 	u64 stop;
 	u64 delta;
-	s64 stddev;
+	u64 stddev;
 	u64 seed;
 	u64 last_seed;
 	unsigned int avg;