diff --git a/test/benchmark/test-benchmark-http.js b/test/benchmark/test-benchmark-http.js
index 65165c41135..d0c9ef17553 100644
--- a/test/benchmark/test-benchmark-http.js
+++ b/test/benchmark/test-benchmark-http.js
@@ -29,7 +29,8 @@ runBenchmark('http',
                'n=1',
                'res=normal',
                'type=asc',
-               'value=X-Powered-By'
+               'value=X-Powered-By',
+               'headerDuplicates=1',
              ],
              {
                NODEJS_BENCHMARK_ZERO_ALLOWED: 1,