[UR][L0] Prefer to build to a device in the context where the first(!…

…) queue is created

Co-authored-by: Sergey Maslov <sergey.v.maslov@intel.com>
Signed-off-by: Spruit, Neil R <neil.r.spruit@intel.com>

source/adapters/level_zero/context.hpp

@@ -51,6 +51,13 @@ struct ur_context_handle_t_ : _ur_object {
   std::vector<ur_device_handle_t> Devices;
   uint32_t NumDevices{};
 
+  // Selects the single device in the context to which the urProgramBuild
+  // should choose to build the program to.
+  // TODO: this should be removed and program should be built to all the
+  // devices in the context (possibly on demand only).
+  //
+  ur_device_handle_t Build2Device = nullptr;
+
   // Immediate Level Zero command list for the device in this context, to be
   // used for initializations. To be created as:
   // - Immediate command list: So any command appended to it is immediately

source/adapters/level_zero/program.cpp

@@ -142,7 +142,10 @@ UR_APIEXPORT ur_result_t UR_APICALL urProgramBuild(
   ZeModuleDesc.pBuildFlags = Options;
   ZeModuleDesc.pConstants = Shim.ze();
 
-  ze_device_handle_t ZeDevice = Context->Devices[0]->ZeDevice;
+  auto Build2Device = Context->Build2Device;
+  if (!Build2Device)
+    Build2Device = Context->Devices[0];
+  ze_device_handle_t ZeDevice = Build2Device->ZeDevice;
   ze_context_handle_t ZeContext = Program->Context->ZeContext;
   ze_module_handle_t ZeModule = nullptr;
 

source/adapters/level_zero/queue.cpp

@@ -294,21 +294,22 @@ UR_APIEXPORT ur_result_t UR_APICALL urQueueCreate(
   { // Lock context for thread-safe update
     std::scoped_lock<ur_shared_mutex> Lock(Context->Mutex);
     UR_ASSERT(Context->isValidDevice(Device), UR_RESULT_ERROR_INVALID_DEVICE);
-
-    auto MakeFirst = Context->Devices.begin();
-    for (auto I = Context->Devices.begin(); I != Context->Devices.end(); ++I) {
-      if (*I == Device) {
-        MakeFirst = I;
-        if (!Device->RootDevice)
-          break;
-        // continue the search for possible root-device in the context
-      } else if (*I == Device->RootDevice) {
-        MakeFirst = I;
-        break; // stop the search
+    if (!Context->Build2Device) {
+      auto DeviceIt = Context->Devices.begin();
+      for (auto I = Context->Devices.begin(); I != Context->Devices.end();
+           ++I) {
+        if (*I == Device) {
+          DeviceIt = I;
+          if (!Device->RootDevice)
+            break;
+          // continue the search for possible root-device in the context
+        } else if (*I == Device->RootDevice) {
+          DeviceIt = I;
+          break; // stop the search
+        }
       }
+      Context->Build2Device = *DeviceIt;
     }
-    if (MakeFirst != Context->Devices.begin())
-      std::iter_swap(MakeFirst, Context->Devices.begin());
   }
   ur_queue_flags_t Flags{};
   if (Props) {