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The-OpenROAD-Project / OpenLane

OpenLane is an automated RTL to GDSII flow based on several components including OpenROAD, Yosys, Magic, Netgen and custom methodology scripts for design exploration and optimization.
https://openlane.readthedocs.io/
Apache License 2.0
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yosys_rewrite_verilog.tcl step seems to get stuck #68

Closed growly closed 3 years ago

growly commented 3 years ago

I'm on rc3 -

The yosys_rewrite_verilog.tcl step of this flow is taking a strangely long time. yosys is consuming ~92 GB of RAM and has been spinning a core at ~100% for 16.5 hours.

The command is yosys -c /openLANE_flow/scripts/yosys_rewrite_verilog.tcl -l /openLANE_flow/designs/151/runs/06-10_16-40/logs/synthesis/yosys_rewrite_verilog.log, but the log file is empty. I believe it's still in the read_verilog step of the script but I can't really be sure. The design is the same as in #39.

I had a stab at debugging yosys; it gets stuck in a recursive call and I couldn't observe progress over a few hours. It might just be really slow.

I built Yosys at HEAD instead and this problem seems to have gone away, with the rewrite step now completing in ~7 hours.

Has anyone else run into this problem with the yosys commit in rc3? (347dd01c2f7dff6e8222c5f9d360f84a17c937b5)

ax3ghazy commented 3 years ago

Hi @growly, yes, we have come across similar behaviour on large designs. We should probably reduce the number of times "rewriting verilog" happens; we only do that to keep all gate-level netlists in a canonical format and to avoid issues with the netgen verilog parser.

Good to know that the insane running time is related to the verilog version... I will try the latest HEAD, but just in case, which commit was the one you tried?

Thanks.

growly commented 3 years ago

I'm at commit 347dd01c2f7dff6e8222c5f9d360f84a17c937b5; it definitely seems to have alleviated the problem!

confirm:

yosys --version
Yosys 0.9+2406 (git sha1 347dd01, gcc 8.3.1 -fPIC -Os)
agorararmard commented 3 years ago

@growly: The yosys version has been updated in rc4 and we're no longer facing this. I'll close this issue. Please, reopen, if you found otherwise.