Closes #629

.flake8

@@ -25,6 +25,7 @@ per-file-ignores =
     dpctl/tensor/_usmarray.pyx: E999, E225, E226, E227
     dpctl/tensor/numpy_usm_shared.py: F821
     dpctl/tests/_cython_api.pyx: E999, E225, E227, E402
+    dpctl/utils/_compute_follows_data.pyx: E999, E225, E227
     examples/cython/sycl_buffer/_buffer_example.pyx: E999, E225, E402
     examples/cython/sycl_direct_linkage/_buffer_example.pyx: E999, E225, E402
     examples/cython/usm_memory/blackscholes.pyx: E999, E225, E226, E402

dpctl/tests/test_utils.py

@@ -0,0 +1,71 @@
+#                      Data Parallel Control (dpctl)
+#
+# Copyright 2020-2021 Intel Corporation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+""" Defines unit test cases for utility functions.
+"""
+
+import pytest
+
+import dpctl
+import dpctl.utils
+
+
+def test_get_execution_queue_input_validation():
+    with pytest.raises(TypeError):
+        dpctl.utils.get_execution_queue(dict())
+
+
+def test_get_execution_queue():
+    try:
+        q = dpctl.SyclQueue()
+        q2 = dpctl.SyclQueue()
+    except dpctl.SyclQueueCreationError:
+        pytest.skip("Queue could not be create for default device")
+
+    exec_q = dpctl.utils.get_execution_queue(())
+    assert exec_q is None
+
+    exec_q = dpctl.utils.get_execution_queue([q])
+    assert exec_q is q
+
+    exec_q = dpctl.utils.get_execution_queue([q, q, q, q])
+    assert exec_q is q
+
+    exec_q = dpctl.utils.get_execution_queue((q, q, None, q))
+    assert exec_q is None
+
+    exec_q = dpctl.utils.get_execution_queue(
+        (
+            q,
+            q2,
+            q,
+        )
+    )
+    assert exec_q is q
+
+
+def test_get_execution_queue_nonequiv():
+    try:
+        q = dpctl.SyclQueue("cpu")
+        d1, d2 = q.sycl_device.create_sub_devices(partition=[1, 1])
+        ctx = dpctl.SyclContext([q.sycl_device, d1, d2])
+        q1 = dpctl.SyclQueue(ctx, d1)
+        q2 = dpctl.SyclQueue(ctx, d2)
+    except dpctl.SyclQueueCreationError:
+        pytest.skip("Queue could not be create for default device")
+
+    exec_q = dpctl.utils.get_execution_queue((q, q1, q2))
+    assert exec_q is None

dpctl/utils/__init__.py

@@ -0,0 +1,5 @@
+from ._compute_follows_data import get_execution_queue
+
+__all__ = [
+    "get_execution_queue",
+]

dpctl/utils/_compute_follows_data.pyx

@@ -0,0 +1,68 @@
+#                      Data Parallel Control (dpctl)
+#
+# Copyright 2020-2021 Intel Corporation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# distutils: language = c++
+# cython: language_level=3
+# cython: linetrace=True
+
+"""This file implements Python buffer protocol using Sycl USM shared and host
+allocators. The USM device allocator is also exposed through this module for
+use in other Python modules.
+"""
+
+
+import dpctl
+
+from .._sycl_queue cimport SyclQueue
+
+__all__ = ["get_execution_queue", ]
+
+
+cdef bint queue_equiv(SyclQueue q1, SyclQueue q2):
+    """ Queues are equivalent if contexts are the same,
+    devices are the same, and properties are the same."""
+    return (
+        (q1 is q2) or
+        (
+            (q1.sycl_context == q2.sycl_context) and
+            (q1.sycl_device == q2.sycl_device) and
+            (q1.is_in_order == q2.is_in_order) and
+            (q1.has_enable_profiling == q2.has_enable_profiling)
+        )
+    )
+
+
+def get_execution_queue(qs):
+    """ Given a list of :class:`dpctl.SyclQueue` objects
+    returns the execution queue under compute follows data paradigm,
+    or returns `None` if queues are not equivalent.
+    """
+    if not isinstance(qs, (list, tuple)):
+        raise TypeError(
+            "Expected a list or a tuple, got {}".format(type(qs))
+        )
+    if len(qs) == 0:
+        return None
+    elif len(qs) == 1:
+        return qs[0] if isinstance(qs[0], dpctl.SyclQueue) else None
+    for q1, q2 in zip(qs, qs[1:]):
+        if not isinstance(q1, dpctl.SyclQueue):
+            return None
+        elif not isinstance(q2, dpctl.SyclQueue):
+            return None
+        elif not queue_equiv(<SyclQueue> q1, <SyclQueue> q2):
+             return None
+    return qs[0]

setup.py

@@ -214,6 +214,13 @@ def extensions():
             ],
             **extension_args,
         ),
+        Extension(
+            "dpctl.utils._compute_follows_data",
+            [
+                os.path.join("dpctl", "utils", "_compute_follows_data.pyx"),
+            ],
+            **extension_args,
+        ),
         Extension(
             "dpctl.tensor._usmarray",
             [