dvpp_malloc

Applicability

Description

Allocates device memory. The requested allocation must meet the media data processing requirements (for example,128-byte alignment of the start address).

Prototype

• C Prototype

  1	hi_s32 hi_mpi_dvpp_malloc(hi_u32 dev_id, hi_void **dev_ptr, hi_u64 size)

• Python Function

  1	dev_ptr, ret = acl.himpi.dvpp_malloc(dev_id, size)

Parameters

Return Value

Restrictions

• After this API is called to allocate memory, the lifetime of the memory is managed by the user. If the memory is not used, the acl.himpi.dvpp_free API must be called to free the memory in a timely manner.
• Memory allocated by this API call is accessible only to the calling process and cannot be shared among processes.
• Media data processing can access a maximum of 16 GB address space in each process.

  This restriction applies to the following products:

  Atlas A3 training product / Atlas A3 inference product

  Atlas A2 training product / Atlas A2 inference product

  Atlas inference product

• When acl.himpi.dvpp_malloc is called to allocate the memory, the allocation size is the input size rounded up to the nearest multiple of 32, plus 32 bytes.
• When the output of media data processing is used as the input of model inference, if you use this API to allocate a large memory block and divide and manage the memory, each memory segment must meet the following requirements:
  • The memory size is rounded up to the nearest multiple of 32 plus 32 bytes (m = ALIGN_UP[len,32] + 32 bytes).
  • The memory start address must be 128-byte aligned (ALIGN_UP[m,128]).
  

  len indicates the size of a memory segment. ALIGN_UP[len,k] indicates rounding up to a multiple of k bytes as in this formula: ((len – 1)/k + 1) x k.

Reference

For details about the API call sequence, see Media Data Processing V2.