Test using pytest-run-parallel and related fixups in the tests

ci/tools/run-tests

@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 
-# SPDX-FileCopyrightText: Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-FileCopyrightText: Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
 #
 # SPDX-License-Identifier: Apache-2.0
 
@@ -20,6 +20,14 @@ fi
 
 test_module=${1}
 
+FREE_THREADING=""
+PYTEST_PARALLEL_ARGS=()
+if python -c 'import sys; assert not sys._is_gil_enabled()' 2> /dev/null; then
+  FREE_THREADING="-ft"
+  PYTEST_PARALLEL_ARGS=(--parallel-threads=4)
+  pip install pytest-run-parallel
+fi
+
 # For standard modes, install pathfinder up front (it is a direct dependency
 # of bindings, and a transitive dependency of core).  Nightly modes install
 # all wheels together in a single pip call further below.
@@ -36,7 +44,7 @@ if [[ "${test_module}" == "pathfinder" ]]; then
     "LD:${CUDA_PATHFINDER_TEST_LOAD_NVIDIA_DYNAMIC_LIB_STRICTNESS} " \
     "FH:${CUDA_PATHFINDER_TEST_FIND_NVIDIA_HEADERS_STRICTNESS} " \
     "BC:${CUDA_PATHFINDER_TEST_FIND_NVIDIA_BITCODE_LIB_STRICTNESS}"
-  pytest -ra -s -v --durations=0 tests/ |& tee /tmp/pathfinder_test_log.txt
+  pytest -ra -s -v --durations=0 "${PYTEST_PARALLEL_ARGS[@]}" tests/ |& tee /tmp/pathfinder_test_log.txt
   # Report the number of "INFO test_" lines (including zero)
   # to support quick validations based on GHA log archives.
   line_count=$(awk '/^INFO test_/ {count++} END {print count+0}' /tmp/pathfinder_test_log.txt)
@@ -51,21 +59,16 @@ elif [[ "${test_module}" == "bindings" ]]; then
     pip install $(ls "${CUDA_BINDINGS_ARTIFACTS_DIR}"/*.whl)[all] --group test
   fi
   echo "Running bindings tests"
-  ${SANITIZER_CMD} pytest -rxXs -v --durations=0 --randomly-dont-reorganize tests/
+  ${SANITIZER_CMD} pytest -rxXs -v --durations=0 --randomly-dont-reorganize "${PYTEST_PARALLEL_ARGS[@]}" tests/
   if [[ "${SKIP_CYTHON_TEST}" == 0 ]]; then
-    ${SANITIZER_CMD} pytest -rxXs -v --durations=0 --randomly-dont-reorganize tests/cython
+    ${SANITIZER_CMD} pytest -rxXs -v --durations=0 --randomly-dont-reorganize "${PYTEST_PARALLEL_ARGS[@]}" tests/cython
   fi
   popd
 elif [[ "${test_module}" == "core" || "${test_module}" == nightly-* ]]; then
   # Shared setup for core and nightly modes.
   TEST_CUDA_MAJOR="$(cut -d '.' -f 1 <<< ${CUDA_VER})"
   CUDA_VER_MINOR="$(cut -d '.' -f 1-2 <<< "${CUDA_VER}")"
 
-  FREE_THREADING=""
-  if python -c 'import sys; assert not sys._is_gil_enabled()' 2> /dev/null; then
-    FREE_THREADING+="-ft"
-  fi
-
   # Resolve bindings based on BINDINGS_SOURCE (set by env-vars):
   #   main/backport → local wheel from artifacts dir
   #   published     → install from PyPI by version
@@ -105,11 +108,11 @@ elif [[ "${test_module}" == "core" || "${test_module}" == nightly-* ]]; then
     echo "Installed packages before core tests:"
     pip list
     echo "Running core tests"
-    ${SANITIZER_CMD} pytest -rxXs -v --durations=0 --randomly-dont-reorganize tests/
+    ${SANITIZER_CMD} pytest -rxXs -v --durations=0 --randomly-dont-reorganize "${PYTEST_PARALLEL_ARGS[@]}" tests/
     # Currently our CI always installs the latest bindings (from either major version).
     # This is not compatible with the test requirements.
     if [[ "${SKIP_CYTHON_TEST}" == 0 ]]; then
-      ${SANITIZER_CMD} pytest -rxXs -v --durations=0 --randomly-dont-reorganize tests/cython
+      ${SANITIZER_CMD} pytest -rxXs -v --durations=0 --randomly-dont-reorganize "${PYTEST_PARALLEL_ARGS[@]}" tests/cython
     fi
     popd
   elif [[ "${test_module}" == "nightly-cuda-core" ]]; then

cuda_bindings/tests/test_cufile.py

@@ -138,7 +138,7 @@ def ctx():
     (err,) = cuda.cuCtxSetCurrent(ctx)
     assert err == cuda.CUresult.CUDA_SUCCESS
 
-    yield
+    yield ctx
 
     cuda.cuDevicePrimaryCtxRelease(device)
 

cuda_bindings/tests/test_examples.py

@@ -20,6 +20,7 @@ def test_example(example):
 
     env = os.environ.copy()
     env["CUDA_BINDINGS_SKIP_EXAMPLE"] = "100"
+    env["MPLBACKEND"] = "Agg"  # avoid plt.show() from blocking
 
     process = subprocess.run([sys.executable, example], capture_output=True, env=env)  # noqa: S603
     # returncode is a special value used in the examples to indicate that system requirements are not met.

cuda_core/cuda/core/_device_resources.pxd

@@ -2,8 +2,6 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
-cimport cython
-
 from cuda.bindings cimport cydriver
 from cuda.core._resource_handles cimport ContextHandle, GreenCtxHandle
 
@@ -17,7 +15,6 @@ cdef class SMResource:
         unsigned int _flags
         bint _is_usable
         object __weakref__
-        cython.pymutex _split_mutex
 
     @staticmethod
     cdef SMResource _from_dev_resource(cydriver.CUdevResource res, int device_id)

cuda_core/cuda/core/_device_resources.pyx

@@ -498,11 +498,10 @@ cdef class SMResource:
         )
         _resolve_group_count(opts)
         _check_green_ctx_support()
-        with self._split_mutex:
-            if _can_use_structured_sm_split():
-                return _split_with_general_api(self, opts, dry_run)
-            # SplitByCount requires the same 12.4+ as green ctx support (already checked above)
-            return _split_with_count_api(self, opts, dry_run)
+        if _can_use_structured_sm_split():
+            return _split_with_general_api(self, opts, dry_run)
+        # SplitByCount requires the same 12.4+ as green ctx support (already checked above)
+        return _split_with_count_api(self, opts, dry_run)
 
 
 cdef class WorkqueueResource:

cuda_core/tests/conftest.py

@@ -131,6 +131,18 @@ def wrapper(*args, **kwargs):
                 kwargs["mempool_device_x2"] = _mempool_device_impl(2)
             if "mempool_device_x3" in kwargs:
                 kwargs["mempool_device_x3"] = _mempool_device_impl(3)
+
+            # These are used by test_green_context.py.  The original fixtures include
+            # pytest.skip() but that should have correctly fired by this time.
+            if "sm_resource" in kwargs:
+                kwargs["sm_resource"] = device.resources.sm
+            if "wq_resource" in kwargs:
+                kwargs["wq_resource"] = device.resources.workqueue
+            if "green_ctx" in kwargs:
+                from cuda.core import ContextOptions, SMResourceOptions
+
+                groups, _ = device.resources.sm.split(SMResourceOptions(count=None))
+                kwargs["green_ctx"] = device.create_context(ContextOptions(resources=[groups[0]]))
             return func(*args, **kwargs)
 
     wrapper._cuda_core_worker_cuda_wrapped = True