Investigate OpenROAD global-route repair_timing correctly — the grt "grind"/timeout, hold- and setup-buffer insertion. Covers why a skip-repair (fast) grt measures nothing about repair, why repair_timing must run inside global_route.tcl on the pre-GR ODB, how…
Ask whether a target is a remote cache hit on this machine without building it (a capture kills every miss as it appears and lists the actions behind it as not reached, minutes on a laptop), and find out why it is not when another machine built it: a few…
The standing rules learned building XiangShan with bazel-orfs, for any large design: fix the tools and never the design (no multicycle or false-path exceptions, no added RTL registers); hard stops where a problem is made; finish the macros before the parent;…
How to constrain a hardened macro or block: only register-to-register paths can fail timing closure, boundary paths are optimization targets written with set_max_delay, and set_input_delay/set_output_delay cannot be written at all without assuming a clock…
Choose which modules of a large design to harden as macros by their interfaces in space (pins per micron of perimeter, from the RTL) and in time (registered, shallow boundary crossings, from a hierarchical synthesis), then plan the parent floorplan those…
Set SYNTH_HDL_FRONTEND=slang for synthesis unless the design's Verilog cannot go through slang; yosys's own Verilog frontend is effectively deprecated for SystemVerilog and its generate-block expansion can take minutes on a netlist that synthesises in…
Ask a placed or routed design questions through a persistent OpenROAD session on a flow stage's ODB (the odb-debug daemon and its MCP tools): where the macros are, which cells sit inside a macro footprint or in a sliver between macros, what check_placement…
Settle open questions with the human at small scale and fast turnaround (seconds to minutes: synthetic design, checkpoint, single stage, unit test) before any long run, then declare the long run and how many hours it needs no input, and run it unattended with…