Function: malloc_physical

Applicability

Product	Supported (√/x)
Atlas A3 training products/Atlas A3 inference products	√
Atlas A2 training products/Atlas A2 inference products	√
Atlas training products	√
Atlas inference products	√
Atlas 200I/500 A2 inference products	√

Function Usage

Allocates physical host or device memory. A physical memory handle will be returned.

This API can be used together with acl.rt.reserve_mem_address (for allocating virtual memory) and acl.rt.map_mem (for establishing the mapping between the virtual memory and the physical memory) to allocate virtual memory with consecutive addresses and maximize the use of physical memory addresses.

This API can be used together with acl.rt.mem_export_to_shareable_handle (for exporting the physical memory handle) and acl.rt.mem_import_from_shareable_handle (for importing the shared handle) to implement physical memory sharing among multiple processes. In addition, the virtual memory can be used when the physical memory is shared. For details, see the description of acl.rt.mem_export_to_shareable_handle.

Atlas 200/300/500 inference products: This API is not supported.

Prototype

C Prototype

aclError aclrtMallocPhysical(aclrtDrvMemHandle *handle, size_t size, const aclrtPhysicalMemProp *prop, uint64_t flags)

Python Function

handle, ret = acl.rt.malloc_physical(size, prop, flags)

Parameter Description

Parameter	Description
size	Int, size of the physical address space, in bytes. Call acl.rt.mem_get_allocation_granularity to obtain the memory granularity, and then call this API to allocate the physical memory. The size is aligned based on the obtained memory granularity to save memory.
prop	Dict, physical memory attributes. For details, see aclrtPhysicalMemProp.
flags	Int, reserved. Currently, this parameter can only be set to 0.

Parameter

Description

size

Int, size of the physical address space, in bytes.

Call acl.rt.mem_get_allocation_granularity to obtain the memory granularity, and then call this API to allocate the physical memory. The size is aligned based on the obtained memory granularity to save memory.

prop

Dict, physical memory attributes. For details, see aclrtPhysicalMemProp.

flags

Int, reserved. Currently, this parameter can only be set to 0.

Return Value Description

Return Value	Description
handle	Int, handle for storing physical memory information.
ret	Int, error code: 0 on success; else, failure.

Restrictions

Atlas 200I/500 A2 inference products: This API is not supported in Ascend RC form.
In the current version, only the ACL_HBM_MEM_HUGE (2 MB aligned huge page), ACL_HBM_MEM_HUGE1G (1 GB aligned huge page), and ACL_HBM_MEM_NORMAL (normal page) memory types are supported. However, if ACL_HBM_MEM_NORMAL is passed, the system uses ACL_HBM_MEM_HUGE instead.
For products that do not have HBM memory on the following devices, the system automatically allocates the DDR memory of the ACL_DDR_MEM_HUGE type.
- Atlas inference products
- Atlas 200I/500 A2 inference products
The support for the ACL_HBM_MEM_HUGE1G option varies with the product model.
- The Atlas A3 training products/Atlas A3 inference products supports this option.
- The Atlas A2 training products/Atlas A2 inference products supports this option.
- The Atlas 200I/500 A2 inference products does not support this option.
- The Atlas inference products does not support this option.
- The Atlas training products does not support this option.

Parent topic: Memory Management