diff --git a/src/common.cu b/src/common.cu
index d3fb87aea9..4d9e302802 100644
--- a/src/common.cu
+++ b/src/common.cu
@@ -641,7 +641,7 @@ testResult_t TimeTest(struct threadArgs* args, ncclDataType_t type, const char*
   // Warm-up for small size
   setupArgs(args->minbytes, type, args);
   for (int iter = 0; iter < warmup_iters; iter++) {
-    TESTCHECK(startColl(args, type, op, root, 0, iter));
+    TESTCHECK(startColl(args, type, op, root, iter < warmup_iters/2 ? 0 : 1, iter));
   }
   TESTCHECK(completeColl(args));