Add experimental option to force discovery of all copy agents.

Discards all user provided async copy agent info and relies on
pointer info discovery.

Change-Id: Ife3e708a49ffccbede4983ab47d5ed0032970857

runtime/hsa-runtime/core/runtime/runtime.cpp

@@ -469,8 +469,9 @@ hsa_status_t Runtime::CopyMemory(void* dst, core::Agent* dst_agent, const void*
                                  core::Agent* src_agent, size_t size,
                                  std::vector<core::Signal*>& dep_signals,
                                  core::Signal& completion_signal) {
+
   auto lookupAgent = [this](core::Agent* agent, const void* ptr) {
-    if (agent == nullptr) {
+    if (agent == nullptr || flag().discover_copy_agents()) {
       hsa_amd_pointer_info_t info;
       PtrInfoBlockData block;
       info.size = sizeof(info);
@@ -628,11 +629,11 @@ hsa_status_t Runtime::GetSystemInfo(hsa_system_info_t attribute, void* value) {
       break;
     }
     case HSA_AMD_SYSTEM_INFO_SVM_SUPPORTED: {
-      bool ret = true;
-      for (auto agent : gpu_agents_) {
-        AMD::GpuAgent* gpu = (AMD::GpuAgent*)agent;
-        ret &= (gpu->properties().Capability.ui32.SVMAPISupported == 1);
-      }
+      bool ret = true;
+      for (auto agent : gpu_agents_) {
+        AMD::GpuAgent* gpu = (AMD::GpuAgent*)agent;
+        ret &= (gpu->properties().Capability.ui32.SVMAPISupported == 1);
+      }
       *(bool*)value = ret;
       break;
     }

runtime/hsa-runtime/core/util/flag.h

@@ -153,6 +153,9 @@ class Flag {
     // Will become opt-out and possibly removed in future releases.
     var = os::GetEnvVar("HSA_COOP_CU_COUNT");
     coop_cu_count_ = (var == "1") ? true : false;
+
+    var = os::GetEnvVar("HSA_DISCOVER_COPY_AGENTS");
+    discover_copy_agents_ = (var == "1") ? true : false;
   }
 
   void parse_masks(uint32_t maxGpu, uint32_t maxCU) {
@@ -221,6 +224,8 @@ class Flag {
 
   bool coop_cu_count() const { return coop_cu_count_; }
 
+  bool discover_copy_agents() const { return discover_copy_agents_; }
+
  private:
   bool check_flat_scratch_;
   bool enable_vm_fault_message_;
@@ -241,6 +246,7 @@ class Flag {
   bool debug_;
   bool cu_mask_skip_init_;
   bool coop_cu_count_;
+  bool discover_copy_agents_;
 
   SDMA_OVERRIDE enable_sdma_;