Use setdefault-oriented cache updates in core hot paths

Switch selected cache write sites to setdefault/get-based patterns and
keep explicit comments where setdefault is intentionally not used for
primitive value caches.

Signed-off-by: Sebastian Berg <sebastianb@nvidia.com>

Author: seberg

cuda_core/cuda/core/_device.pyx

@@ -85,9 +85,12 @@ cdef class DeviceProperties:
 
     cdef inline int _get_cached_attribute(self, attr, default=0) except? -2:
         """Retrieve the attribute value, using cache if applicable."""
-        if attr not in self._cache:
-            self._cache[attr] = self._get_attribute(attr, default)
-        return self._cache[attr]
+        cached = self._cache.get(attr)
+        if cached is not None:
+            return cached
+        cdef int value = self._get_attribute(attr, default)
+        self._cache[attr] = value  # setdefault not needed for ints
+        return value
 
     @property
     def max_threads_per_block(self) -> int:
@@ -1131,11 +1134,11 @@ class Device:
     def compute_capability(self) -> ComputeCapability:
         """Return a named tuple with 2 fields: major and minor."""
         cdef DeviceProperties prop = self.properties
-        if "compute_capability" in prop._cache:
-            return prop._cache["compute_capability"]
+        cached = prop._cache.get("compute_capability")
+        if cached is not None:
+            return cached
         cc = ComputeCapability(prop.compute_capability_major, prop.compute_capability_minor)
-        prop._cache["compute_capability"] = cc
-        return cc
+        return prop._cache.setdefault("compute_capability", cc)
 
     @property
     def arch(self) -> str:

cuda_core/cuda/core/_memory/_graph_memory_resource.pyi

@@ -2,8 +2,6 @@
 
 from __future__ import annotations
 
-from functools import cache
-
 from cuda.core._device import Device
 from cuda.core._memory._buffer import Buffer, MemoryResource
 from cuda.core._stream import Stream
@@ -113,7 +111,6 @@ class GraphMemoryResource(cyGraphMemoryResource):
         ...
 
     @classmethod
-    @cache
     def _create(cls, device_id: int) -> GraphMemoryResource:
         ...
 __all__ = ['GraphMemoryResource']

cuda_core/cuda/core/_memory/_graph_memory_resource.pyx

@@ -18,7 +18,6 @@ from cuda.core._resource_handles cimport (
 from cuda.core._stream cimport Stream_accept, Stream
 from cuda.core._utils.cuda_utils cimport HANDLE_RETURN
 
-from functools import cache
 from typing import TYPE_CHECKING
 
 if TYPE_CHECKING:
@@ -161,6 +160,8 @@ cdef class cyGraphMemoryResource(MemoryResource):
         return False
 
 
+cdef dict _mem_resource_cache = {}
+
 class GraphMemoryResource(cyGraphMemoryResource):
     """
     A memory resource for memory related to graphs.
@@ -185,9 +186,16 @@ class GraphMemoryResource(cyGraphMemoryResource):
         return cls._create(c_device_id)
 
     @classmethod
-    @cache
     def _create(cls, int device_id) -> GraphMemoryResource:
-        return cyGraphMemoryResource.__new__(cls, device_id)
+        # we use a dict currently, because functools.cache is currently less
+        # thread-safe see also: https://github.com/python/cpython/issues/150708
+        res = _mem_resource_cache.get(device_id)
+        if res is not None:
+            return res
+
+        # create new instance, but in case of a race may return another:
+        new = cyGraphMemoryResource.__new__(cls, device_id)
+        return _mem_resource_cache.setdefault(device_id, new)
 
 
 # Raise an exception if the given stream is capturing.

cuda_core/cuda/core/_memoryview.pyx

@@ -80,7 +80,7 @@ cdef inline bint _is_torch_tensor(object obj):
     cdef str mod = tp.__module__ or ""
     cdef bint result = mod.startswith("torch") and hasattr(obj, "data_ptr") \
         and _torch_version_check()
-    _torch_type_cache[tp] = result
+    _torch_type_cache[tp] = result  # setdefault not needed for bools
     return result
 
 

cuda_core/cuda/core/_module.pyx

@@ -83,7 +83,7 @@ cdef class KernelAttributes:
         cdef int result
         with nogil:
             HANDLE_RETURN(cydriver.cuKernelGetAttribute(&result, attribute, as_cu(self._h_kernel), device_id))
-        self._cache[cache_key] = result
+        self._cache[cache_key] = result  # setdefault not needed for ints
         return result
 
     def __getitem__(self, device: Device | int) -> KernelAttributes:

cuda_core/cuda/core/graph/_graph_node.pyx

@@ -78,8 +78,7 @@ _node_registry: weakref.WeakValueDictionary[int, GraphNode] = weakref.WeakValueD
 
 
 cdef inline GraphNode _registered(GraphNode n):
-    _node_registry[<uintptr_t>n._h_node.get()] = n
-    return n
+    return _node_registry.setdefault(<uintptr_t>n._h_node.get(), n)
 
 
 cdef class GraphNode: