Host Buffer Alignment - 2021.1 English

Vitis Guidance Messaging (UG1315)

Document ID
UG1315
Release Date
2021-06-16
Version
2021.1 English

Description

Ensure the memory pointer is page-aligned while creating a buffer in the host code.

Explanation

Xilinx® runtime (XRT) prefers page-aligned memory for efficient data transfer to and from the FPGA. If the buffer pointer is not aligned to a page boundary, XRT performs extra memcpy to make it aligned. This extra memcpy operation can be avoided if host code memory is aligned to page boundary.

Resolution

Use posix_memalign, aligned_alloc, _aligned_malloc, and so on to align the cl_buffer host pointer to the page boundary.