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Mojo struct
AccessPolicyWindow
struct AccessPolicyWindow
Specifies an access policy for a window of memory.
This struct defines a contiguous extent of memory beginning at base_ptr and ending at base_ptr + num_bytes, with associated access policies. It allows fine-grained control over how memory is accessed and cached, which can significantly impact performance for memory-bound workloads.
The window is partitioned into segments with different access properties based on the hit_ratio. Accesses to "hit segments" use the hit_prop policy, while accesses to "miss segments" use the miss_prop policy.
Note:
The num_bytes value is limited by CU_DEVICE_ATTRIBUTE_MAX_ACCESS_POLICY_WINDOW_SIZE.
The CUDA driver may align the base_ptr and restrict the maximum size.
Fields
- base_ptr (
Optional[Pointer[NoneType, MutUntrackedOrigin]]): Starting address of the access policy window. Driver may align it. - num_bytes (
Int): Size in bytes of the window policy. CUDA driver may restrict the maximum size and alignment. - hit_ratio (
Float32): Specifies percentage of lines assigned hit_prop, rest are assigned miss_prop. Value should be between 0.0 and 1.0. - hit_prop (
AccessProperty): AccessProperty applied to hit segments within the window. - miss_prop (
AccessProperty): AccessProperty applied to miss segments within the window. Must be either NORMAL or STREAMING.
Implemented traits
AnyType,
Copyable,
Defaultable,
Deinitable,
ImplicitlyCopyable,
Movable,
RegisterPassable,
Writable
Methods
__init__
def __init__() -> Self
Initializes a new AccessPolicyWindow with default values.
def __init__[T: AnyType](*, base_ptr: Pointer[T, address_space=base_ptr.address_space], count: Int, hit_ratio: Float32, hit_prop: AccessProperty = AccessProperty.NORMAL, miss_prop: AccessProperty = AccessProperty.NORMAL) -> Self
Initializes an AccessPolicyWindow for a typed memory region.
Parameters:
- T (
AnyType): The type of data in the memory region.
Args:
- base_ptr (
Pointer[T, address_space=base_ptr.address_space]): Pointer to the start of the memory region. - count (
Int): Number of elements of type T in the memory region. - hit_ratio (
Float32): Fraction of the window that should use hit_prop (0.0 to 1.0). - hit_prop (
AccessProperty): Access property for hit segments (default: NORMAL). - miss_prop (
AccessProperty): Access property for miss segments (default: NORMAL).
write_to
def write_to(self, mut writer: T)
Writes a string representation of the AccessPolicyWindow to a writer.
This method formats all the fields of the AccessPolicyWindow into a human-readable string representation and writes it to the provided writer.
Args:
- writer (
T): The writer instance to write the formatted string to.