Host Pointer Page Align - 2022.2 English

Vitis Guidance Messaging (UG1315)

Document ID
UG1315
Release Date
2022-10-19
Version
2022.2 English

Description

While creating a buffer in the host code, ensure the memory pointer is page-aligned.

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.