Miscellaneous Options - 2025.2 English - UG1076

AI Engine Tools and Flows User Guide (UG1076)

Document ID
UG1076
Release Date
2025-11-20
Version
2025.2 English
swfifo-threshold

Above this threshold, the system implements a FIFO as a DMA FIFO in an AI Engine application. The system generates an error in an AI Engine-ML application. To avoid an error message in AI Engine-ML, increase the threshold. Increasing the threshold requires additional resources to route the design.

evaluate-fifo-depth

This option analyzes re-convergent data paths. Data can be sent on multiple paths. Sometimes data can re-converge and result in a deadlock. Resolve deadlocks by adding FIFOs to the appropriate data paths.

The steps for evaluating and resolving deadlocks as a result of re-convergent data paths is as follows:

  1. Compile the design with this option.
  2. Run aiesimulator on the design.
  3. Open Vitis Unified IDE with the simulation run_summary.

    Take note of the FIFO depth in theEstimated FIFO column in the Nets table. This FIFO depth value is the recommended value (in 32-bit words) that the fifo_depth(net) constraint uses on a specific net connection in the graph. The purpose is to resolve the deadlock situation.

  4. Apply the recommended FIFO depth value using the fifo_depth constraint on specified nets on the graph, and recompile the design. In AI Engine-ML, if the recommendation is above the current fifo depth threshold, increase it using the swfifo-threshold option.
disable-multirate

Disable multirate in ADF graphs. Accepted values are true and false. The default is false.

disable-multirate=true
known-tripcount
This option converts an unknown trip count to a known trip count. The option takes no arguments and is disabled when omitted.
known-tripcount
no-init
This option disables initialization of window buffers in AI Engine data memory. This option enables faster loading of the binary images into the SystemC-RTL co-simulation framework. Accepted values are true and false. The default is false.
no-init=true
nodot-graph
By default, the AI Engine compiler produces DOT and PNG files to visualize the user-specified graph and its partitioning onto the AI Engines. This option can be used to eliminate the dot graph output. Accepted values are true and false. The default is false.
nodot-graph=true
compile-testbench-only

In HW compilation, the AI Engine compiler allows compilation of main only (graph.cpp test bench) using this flag. This helps to compile graph.cpp separately. The option is useful in scenarios where only main() or the test bench is changed and there are no changes in graph and kernels. This helps save compilation time of the complete AI Engine design and only compile test bench file whenever necessary.

v++ --compile --mode aie --target=hw --aie.compile-testbench-only graph.cpp
Note: The AI Engine compiler assumes that the initial compilation of the AI Engine graph was successful when using compile-testbench-only. Ensure that only the test bench code was modified and that no changes were made to graph or kernels.