Intel® Hyperflex™ Architecture High-Performance Design Handbook

ID 683353
Date 10/04/2021

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5.2. Interpreting Critical Chain Reports

The Compiler identifies the register chains in your design that limit further optimization through Hyper-Retiming. The Compiler refers to these related register-to-register paths as a critical chain. The fMAX of the critical chain and its associated clock domain is limited by the average delay of a register-to-register path, and quantization delays of indivisible circuit elements like routing wires.

The Retiming Limit Details report the limiting reasons preventing further retiming, and the registers and combinational nodes that comprise the chain. The Fast Forward recommendations list the steps you can take to remove critical chains and enable additional register retiming.

After understanding why a particular critical chain limits your design’s performance, you can then make RTL changes to eliminate that bottleneck and increase performance.