[SYCL] properly report supported device partitioning in Level-Zero

sycl/plugins/level_zero/pi_level_zero.cpp

@@ -1232,11 +1232,18 @@ pi_result piDeviceGetInfo(pi_device Device, pi_device_info ParamName,
   case PI_DEVICE_INFO_REFERENCE_COUNT:
     return ReturnValue(pi_uint32{Device->RefCount});
   case PI_DEVICE_INFO_PARTITION_PROPERTIES: {
+    // SYCL spec says: if this SYCL device cannot be partitioned into at least
+    // two sub devices then the returned vector must be empty.
+    uint32_t ZeSubDeviceCount = 0;
+    ZE_CALL(zeDeviceGetSubDevices(ZeDevice, &ZeSubDeviceCount, nullptr));
+    if (ZeSubDeviceCount < 2) {
+      return ReturnValue(pi_device_partition_property{0});
+    }
     // It is debatable if SYCL sub-device and partitioning APIs sufficient to
     // expose Level Zero sub-devices?  We start with support of
-    // "partition_by_affinity_domain" and "numa" but if that doesn't seem to
-    // be a good fit we could look at adding a more descriptive partitioning
-    // type.
+    // "partition_by_affinity_domain" and "next_partitionable" but if that
+    // doesn't seem to be a good fit we could look at adding a more descriptive
+    // partitioning type.
     struct {
       pi_device_partition_property Arr[2];
     } PartitionProperties = {{PI_DEVICE_PARTITION_BY_AFFINITY_DOMAIN, 0}};

sycl/test/on-device/basic_tests/partition_supported.cpp

@@ -0,0 +1,94 @@
+// RUN: %clangxx -fsycl -fsycl-targets=%sycl_triple %s -o %t.out
+// RUN: %CPU_RUN_PLACEHOLDER %t.out
+// RUN: %GPU_RUN_PLACEHOLDER %t.out
+// RUN: %ACC_RUN_PLACEHOLDER %t.out
+
+/* Check that:
+1) [info::device::partition_properties]: returns the partition properties
+supported by this SYCL device; a vector of info::partition_property. If this
+SYCL device cannot be partitioned into at least two sub devices then the
+returned vector **must be empty**.
+
+2) [create_sub_devices()]: If the SYCL device
+does not support info::partition_property::partition_by_affinity_domain or the
+SYCL device does not support the info::partition_affinity_domain provided, an
+exception with the **feature_not_supported error code must be thrown**.
+*/
+
+#include <CL/sycl.hpp>
+
+/** returns true if the device supports a particular affinity domain
+ */
+static bool
+supports_affinity_domain(const cl::sycl::device &dev,
+                         cl::sycl::info::partition_property partitionProp,
+                         cl::sycl::info::partition_affinity_domain domain) {
+  if (partitionProp !=
+      cl::sycl::info::partition_property::partition_by_affinity_domain) {
+    return true;
+  }
+  auto supported =
+      dev.get_info<cl::sycl::info::device::partition_affinity_domains>();
+  for (cl::sycl::info::partition_affinity_domain dom : supported) {
+    if (dom == domain) {
+      return true;
+    }
+  }
+  return false;
+}
+
+/** returns true if the device supports a particular partition property
+ */
+static bool
+supports_partition_property(const cl::sycl::device &dev,
+                            cl::sycl::info::partition_property partitionProp) {
+  auto supported = dev.get_info<cl::sycl::info::device::partition_properties>();
+  for (cl::sycl::info::partition_property prop : supported) {
+    if (prop == partitionProp) {
+      return true;
+    }
+  }
+  return false;
+}
+
+int main() {
+
+  auto dev = cl::sycl::device(cl::sycl::default_selector());
+
+  cl::sycl::info::partition_property partitionProperty =
+      cl::sycl::info::partition_property::partition_by_affinity_domain;
+  cl::sycl::info::partition_affinity_domain affinityDomain =
+      cl::sycl::info::partition_affinity_domain::next_partitionable;
+
+  if (supports_partition_property(dev, partitionProperty)) {
+    if (supports_affinity_domain(dev, partitionProperty, affinityDomain)) {
+      auto subDevices = dev.create_sub_devices<
+          cl::sycl::info::partition_property::partition_by_affinity_domain>(
+          affinityDomain);
+
+      if (subDevices.size() < 2) {
+        std::cerr << "device::create_sub_device(info::partition_affinity_"
+                     "domain) should have returned at least 2 devices"
+                  << std::endl;
+        return -1;
+      }
+    }
+  } else {
+    try {
+      auto subDevices = dev.create_sub_devices<
+          cl::sycl::info::partition_property::partition_by_affinity_domain>(
+          affinityDomain);
+      std::cerr << "device::create_sub_device(info::partition_affinity_domain) "
+                   "should have thrown an exception"
+                << std::endl;
+      return -1;
+    } catch (const cl::sycl::feature_not_supported &e) {
+    } catch (...) {
+      std::cerr << "device::create_sub_device(info::partition_affinity_domain) "
+                   "should have thrown cl::sycl::feature_not_supported"
+                << std::endl;
+      return -1;
+    }
+  }
+  return 0;
+}