aclrtHostRegister
Applicability
Product |
Supported |
|---|---|
Atlas 350 Accelerator Card |
√ |
√ |
|
√ |
|
x |
|
x |
|
x |
Description
Maps and registers the host memory as a memory address that can be accessed by the device, and obtains the mapped device memory address. This address cannot be used for memory operations, such as memory copy.
If the registered ptr is allocated by aclrtMallocHostWithCfg with the attr type set to ACL_RT_MEM_ATTR_VA_FLAG and the value of vaFlag set to 1, the mapped device address is the same as the host address and can be used for memory operations.
To unregister the host memory, call the aclrtHostUnregister API.
Prototype
1 | aclError aclrtHostRegister(void *ptr, uint64_t size, aclrtHostRegisterType type, void **devPtr) |
Parameters
Parameter |
Input/Output |
Description |
|---|---|---|
ptr |
Input |
Host memory address. The host memory address must be 4K-page-aligned. If the OS kernel version is 5.10 or earlier, using non-page-locked memory will cause exceptions. Therefore, you must call aclrtMallocHost to allocate page-locked host memory. If the OS kernel version is later than 5.10, non-page-locked host memory can be used. Therefore, you can either call aclrtMallocHost to allocate page-locked host memory, or call malloc to allocate non-page-locked host memory. |
size |
Input |
Memory size, in bytes |
type |
Input |
Memory registration type. For details about the type definition, see aclrtHostRegisterType. |
devPtr |
Output |
Memory address mapped from the host memory. This address is accessible to the device. |
Returns
0 on success; otherwise, failure. For details, see aclError.