AIE_MEMORY_STALLS - 2022.2 English

Vitis Guidance Messaging (UG1315)

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

Description

This rule checks the amount of memory stalls for AI Engine tiles.

Default Threshold

20.0

Explanation

Reducing memory stalls can improve AI Engine performance. Time AI Engine was in a memory stall. This could be due to multiple reasons such as multiple memory accesses on the same bank in the same cycle, multiple kernels accessing multiple memories on the same bank, etc.

Recommendation

See this link in AI Engine Tools and Flows User Guide (UG1076) for AIE_MEMORY_STALLS.

You can resolve the stall by examining access patterns using trace results and placing the memory on different banks, or using the Aiecompiler "BufferOptLevel" mapper option.

  • Dispatch memories to different banks. (memories include system memory, RTP, window buffers, data memories.
  • If memory banks are exhausted, do profile and trace to find better solution.
  • Specify BufferOptLeveloption in aiecompiler to build the design.