Set CU_CTX_SCHED_BLOCKING_SYNC option in tests. (NVIDIA#1209)

* Set CU_CTX_SCHED_BLOCKING_SYNC option in tests.

* Update cuda_core/tests/conftest.py

Co-authored-by: Leo Fang <leo80042@gmail.com>

---------

Co-authored-by: Leo Fang <leo80042@gmail.com>

Author: Andy-Jost

cuda_core/tests/conftest.py

@@ -2,6 +2,7 @@
 # SPDX-License-Identifier: Apache-2.0
 
 import multiprocessing
+import os
 
 import helpers
 import pytest
@@ -29,6 +30,13 @@ def init_cuda():
     # TODO: rename this to e.g. init_context
     device = Device()
     device.set_current()
+
+    # Set option to avoid spin-waiting on synchronization.
+    if int(os.environ.get("CUDA_CORE_TEST_BLOCKING_SYNC", 0)) != 0:
+        handle_return(
+            driver.cuDevicePrimaryCtxSetFlags(device.device_id, driver.CUctx_flags.CU_CTX_SCHED_BLOCKING_SYNC)
+        )
+
     yield
     _ = _device_unset_current()