[SYCL] Change device preference to acknowledge ESIMD_EMULATOR

SYCL/ESIMD/esimd_test_utils.hpp

@@ -37,17 +37,16 @@ namespace esimd_test {
 class ESIMDSelector : public device_selector {
   // Require GPU device
   virtual int operator()(const device &device) const {
-    if (const char *dev_filter = getenv("SYCL_DEVICE_FILTER")) {
-      std::string filter_string(dev_filter);
-      if (filter_string.find("gpu") != std::string::npos)
-        return device.is_gpu() ? 1000 : -1;
-      std::cerr
-          << "Supported 'SYCL_DEVICE_FILTER' env var values is 'gpu' and '"
-          << filter_string << "' does not contain such substrings.\n";
-      return -1;
+    if (device.get_backend() == backend::ext_intel_esimd_emulator) {
+      return 1000;
+    } else if (device.is_gpu()) {
+      // pick gpu device if esimd not available but give it a lower score in
+      // order not to compete with the esimd in environments where both are
+      // present
+      return 900;
+    } else {
+      return 0;
     }
-    // If "SYCL_DEVICE_FILTER" not defined, only allow gpu device
-    return device.is_gpu() ? 1000 : -1;
   }
 };
 

SYCL/Regression/device_num.cpp

@@ -115,21 +115,33 @@ int GetPreferredDeviceIndex(const std::vector<device> &devices,
       {info::device_type::host, 100}};
   int score = -1;
   int index = -1;
+  int runnerup_index = -1;
+  int eligible_devices = 0;
   int devCount = devices.size();
   for (int i = 0; i < devCount; i++) {
     int dev_score = 0;
     auto deviceType = devices[i].get_info<info::device::device_type>();
     auto backend = devices[i].get_backend();
     if ((type != info::device_type::all) && (deviceType != type))
       continue;
+    ++eligible_devices;
     dev_score = scoreByType.at(deviceType);
     if (backend == backend::ext_oneapi_level_zero)
       dev_score += 100;
     if (dev_score > score) {
       score = dev_score;
+      runnerup_index = index;
       index = i;
     }
   }
+  if (index >= 0 &&
+      devices[index].get_backend() == backend::ext_intel_esimd_emulator &&
+      eligible_devices > 1) {
+    // if we chose ESIMD_EMULATOR, then must only return it if there are no
+    // other suitable devices in the system. Otherwise, we return the runner up
+    // device.
+    return runnerup_index;
+  }
   return index;
 }