Read HCC_OPT_FLUSH and optimize dispatch accordingly.

If HCC is in this mode, we can use less aggressive flushes in some
cases.


[ROCm/hip commit: 1635b8f43f]

projects/hip/src/hip_module.cpp

@@ -320,11 +320,17 @@ hipError_t hipModuleLaunchKernel(hipFunction_t f,
         aql.kernel_object = f._object;
         aql.setup = 3 << HSA_KERNEL_DISPATCH_PACKET_SETUP_DIMENSIONS;
         aql.header =   (HSA_PACKET_TYPE_KERNEL_DISPATCH << HSA_PACKET_HEADER_TYPE) |
-                                    (1 << HSA_PACKET_HEADER_BARRIER) |
-                                    (HSA_FENCE_SCOPE_SYSTEM << HSA_PACKET_HEADER_ACQUIRE_FENCE_SCOPE) |
-                                    (HSA_FENCE_SCOPE_SYSTEM << HSA_PACKET_HEADER_RELEASE_FENCE_SCOPE);
+                       (1 << HSA_PACKET_HEADER_BARRIER);  // TODO - honor queue setting for execute_in_order
 
-        lp.av->dispatch_hsa_kernel(&aql, config[1] /* kernarg*/, kernArgSize);
+        if (HCC_OPT_FLUSH) {
+            aql.header |= (HSA_FENCE_SCOPE_AGENT << HSA_PACKET_HEADER_ACQUIRE_FENCE_SCOPE) |
+                          (HSA_FENCE_SCOPE_AGENT << HSA_PACKET_HEADER_RELEASE_FENCE_SCOPE);
+        } else {
+            aql.header |= (HSA_FENCE_SCOPE_SYSTEM << HSA_PACKET_HEADER_ACQUIRE_FENCE_SCOPE) |
+                          (HSA_FENCE_SCOPE_SYSTEM << HSA_PACKET_HEADER_RELEASE_FENCE_SCOPE);
+        };
+
+        lp.av->dispatch_hsa_kernel(&aql, config[1] /* kernarg*/, kernArgSize, nullptr/*completion_future*/);
 
 
         ihipPostLaunchKernel(f._name, hStream, lp);