Kernel Average Write Size - 2022.2 English

Vitis Guidance Messaging (UG1315)

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

Description

Kernel average write size on a specific port in kilobytes.

Explanation

This message reports how much data was transferred as part of a write operation to the kernel through the memory mapped AXI port on average. Given the fact that the memory data width was specified by the kernel interface definition, it is possible to derive from this message how many data read operations were grouped into a AXI bus burst read operation.

By default, the AXI buffer scheme is setup to support burst read operations. If the average read size divided by word width of the port is close to 1, burst reads are not used.

Recommendation

Enabling burst data transfers can be implemented by having a separate process for reading and writing to the AXI interface. Each of these processes should contain a loop with a simple variable incremented by one to read/write from the port and store the value internally.

Applying the DATAFLOW pragma to these processes surrounding the actual algorithm results in an efficient implementation.