Fix sub devices (#479)

* In CreateSubDevicesEqually and ByCounts check that counts by positive

Also change error handling in CreateSubDevicesByCounts.

* SyclDevice.create_sub_devices checks partition argument better

Use of zero EU counts now raises and error.

* Added tests that handling of partitions with zero EU counts works as designed

* improved error handling of zero count

dpctl-capi/source/dpctl_sycl_device_interface.cpp

@@ -29,6 +29,7 @@
 #include "Support/CBindingWrapping.h"
 #include "dpctl_sycl_device_manager.h"
 #include <CL/sycl.hpp> /* SYCL headers   */
+#include <algorithm>
 #include <cstring>
 
 using namespace cl::sycl;
@@ -577,8 +578,13 @@ DPCTLDevice_CreateSubDevicesEqually(__dpctl_keep const DPCTLSyclDeviceRef DRef,
                                     size_t count)
 {
     vector_class<DPCTLSyclDeviceRef> *Devices = nullptr;
-    auto D = unwrap(DRef);
-    if (D) {
+    if (DRef) {
+        if (count == 0) {
+            std::cerr << "Can not create sub-devices with zero compute units"
+                      << '\n';
+            return nullptr;
+        }
+        auto D = unwrap(DRef);
         try {
             auto subDevices = D->create_sub_devices<
                 info::partition_property::partition_equally>(count);
@@ -610,13 +616,29 @@ DPCTLDevice_CreateSubDevicesByCounts(__dpctl_keep const DPCTLSyclDeviceRef DRef,
                                      size_t ncounts)
 {
     vector_class<DPCTLSyclDeviceRef> *Devices = nullptr;
-    std::vector<size_t> vcounts;
+    std::vector<size_t> vcounts(ncounts);
     vcounts.assign(counts, counts + ncounts);
-    auto D = unwrap(DRef);
-    if (D) {
+    size_t min_elem = *std::min_element(vcounts.begin(), vcounts.end());
+    if (min_elem == 0) {
+        std::cerr << "Can not create sub-devices with zero compute units"
+                  << '\n';
+        return nullptr;
+    }
+    if (DRef) {
+        auto D = unwrap(DRef);
+        vector_class<std::remove_pointer<decltype(D)>::type> subDevices;
         try {
-            auto subDevices = D->create_sub_devices<
+            subDevices = D->create_sub_devices<
                 info::partition_property::partition_by_counts>(vcounts);
+        } catch (feature_not_supported const &fnse) {
+            std::cerr << fnse.what() << '\n';
+            return nullptr;
+        } catch (runtime_error const &re) {
+            // \todo log error
+            std::cerr << re.what() << '\n';
+            return nullptr;
+        }
+        try {
             Devices = new vector_class<DPCTLSyclDeviceRef>();
             for (const auto &sd : subDevices) {
                 Devices->emplace_back(wrap(new device(sd)));
@@ -625,10 +647,6 @@ DPCTLDevice_CreateSubDevicesByCounts(__dpctl_keep const DPCTLSyclDeviceRef DRef,
             delete Devices;
             std::cerr << ba.what() << '\n';
             return nullptr;
-        } catch (feature_not_supported const &fnse) {
-            delete Devices;
-            std::cerr << fnse.what() << '\n';
-            return nullptr;
         } catch (runtime_error const &re) {
             delete Devices;
             // \todo log error

dpctl-capi/tests/test_sycl_device_subdevices.cpp

@@ -92,6 +92,9 @@ TEST_P(TestDPCTLSyclDeviceInterface, ChkCreateSubDevicesEqually)
             EXPECT_NO_FATAL_FAILURE(DPCTLDevice_Delete(pDRef));
             EXPECT_NO_FATAL_FAILURE(DPCTLDeviceVector_Delete(DVRef));
         }
+        EXPECT_NO_FATAL_FAILURE(
+            DVRef = DPCTLDevice_CreateSubDevicesEqually(DRef, 0));
+        EXPECT_TRUE(DVRef == nullptr);
     }
 }
 
@@ -114,7 +117,12 @@ TEST_P(TestDPCTLSyclDeviceInterface, ChkCreateSubDevicesByCounts)
         if (DVRef) {
             EXPECT_TRUE(DPCTLDeviceVector_Size(DVRef) > 0);
             EXPECT_NO_FATAL_FAILURE(DPCTLDeviceVector_Delete(DVRef));
+            DVRef = nullptr;
         }
+        counts[n - 1] = 0;
+        EXPECT_NO_FATAL_FAILURE(
+            DVRef = DPCTLDevice_CreateSubDevicesByCounts(DRef, counts, n));
+        EXPECT_TRUE(DVRef == nullptr);
     }
 }
 

dpctl/_sycl_device.pyx

@@ -720,7 +720,12 @@ cdef class SyclDevice(_SyclDevice):
             the sub-devices.
         """
         cdef DPCTLDeviceVectorRef DVRef = NULL
-        DVRef = DPCTLDevice_CreateSubDevicesEqually(self._device_ref, count)
+        if count > 0:
+            DVRef = DPCTLDevice_CreateSubDevicesEqually(self._device_ref, count)
+        else:
+            raise ValueError(
+                "Creating sub-devices with zero compute units is requested"
+            )
         if DVRef is NULL:
             raise SubDeviceCreationError("Sub-devices were not created.")
         return _get_devices(DVRef)
@@ -734,6 +739,7 @@ cdef class SyclDevice(_SyclDevice):
         """
         cdef int ncounts = len(counts)
         cdef size_t *counts_buff = NULL
+        cdef size_t min_count = 1
         cdef DPCTLDeviceVectorRef DVRef = NULL
         cdef int i
 
@@ -748,10 +754,17 @@ cdef class SyclDevice(_SyclDevice):
             )
         for i in range(ncounts):
             counts_buff[i] = counts[i]
-        DVRef = DPCTLDevice_CreateSubDevicesByCounts(
-            self._device_ref, counts_buff, ncounts
-        )
+            if counts_buff[i] == 0:
+                min_count = 0
+        if min_count:
+            DVRef = DPCTLDevice_CreateSubDevicesByCounts(
+                self._device_ref, counts_buff, ncounts
+            )
         free(counts_buff)
+        if min_count == 0:
+            raise ValueError(
+                "Targeted sub-device execution units must positive"
+            )
         if DVRef is NULL:
             raise SubDeviceCreationError("Sub-devices were not created.")
         return _get_devices(DVRef)

dpctl/tests/test_sycl_device.py

@@ -360,6 +360,13 @@ def check_create_sub_devices_equally(device):
         pytest.fail("create_sub_devices failed")
 
 
+def check_create_sub_devices_equally_zeros(device):
+    try:
+        device.create_sub_devices(partition=0)
+    except TypeError:
+        pass
+
+
 def check_create_sub_devices_by_counts(device):
     try:
         n = device.max_compute_units / 2
@@ -372,6 +379,13 @@ def check_create_sub_devices_by_counts(device):
         pytest.fail("create_sub_devices failed")
 
 
+def check_create_sub_devices_by_counts_zeros(device):
+    try:
+        device.create_sub_devices(partition=(0, 1))
+    except TypeError:
+        pass
+
+
 def check_create_sub_devices_by_affinity_not_applicable(device):
     try:
         device.create_sub_devices(partition="not_applicable")