diff --git a/src/cpu/testers/gpu_ruby_test/gpu_wavefront.cc b/src/cpu/testers/gpu_ruby_test/gpu_wavefront.cc
index ae4078ee6c..0fcfba7a37 100644
--- a/src/cpu/testers/gpu_ruby_test/gpu_wavefront.cc
+++ b/src/cpu/testers/gpu_ruby_test/gpu_wavefront.cc
@@ -189,6 +189,7 @@ GpuWavefront::issueAtomicOps()
                                              AtomicOpFunctorPtr(amo_op));
         req->setPaddr(address);
         req->setReqInstSeqNum(tester->getActionSeqNum());
+        req->setCacheCoherenceFlags(Request::SLC_BIT);
         // set protocol-specific flags
         setExtraRequestFlags(req);