| *** tpb has joined #vtr-dev | 00:00 | |
| litghost | kem_: Any chance you can take a look at https://github.com/verilog-to-routing/vtr-verilog-to-routing/issues/526#issuecomment-481897542 The behavior is confusing, and I want to check if I understand that there is a problem | 18:20 |
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| tpb | Title: Router generating "stub" or "antenna" nets · Issue #526 · verilog-to-routing/vtr-verilog-to-routing · GitHub (at github.com) | 18:20 |
| kem_ | litghost: I'm pretty busy at the moment, so I probably won't get a chance in the near term | 18:38 |
| litghost | kem_: Okay, thanks | 18:38 |
| kem_ | litghost: You might be interested in: https://github.com/verilog-to-routing/vtr-verilog-to-routing/commit/f44241098aea3fd9104ba2e1618091dd66d525ae | 18:38 |
| tpb | Title: vpr: Add initial route tree stub check to check_route · verilog-to-routing/vtr-verilog-to-routing@f442410 · GitHub (at github.com) | 18:38 |
| kem_ | litghost: which is an initial cut of a stub check which runs during check_route | 18:38 |
| kem_ | litghost: Any additional debugging you can do to narrow down/understand the issue would also help | 18:39 |
| litghost | kem_: Let me see if that throws an error on my design | 18:39 |
| litghost | kem_: I believe that was the idea, yes? | 18:39 |
| kem_ | litghost: Yep, although I haven't tested it with non-configurable edges | 18:40 |
| kem_ | litghost: I'm also going to be taking a crack at re-factoring the non-configurable edge routing code (to clean it up and fix stuff like https://github.com/verilog-to-routing/vtr-verilog-to-routing/issues/525) | 18:41 |
| tpb | Title: Improve Router Costing of Non-configurably Connected Nodes · Issue #525 · verilog-to-routing/vtr-verilog-to-routing · GitHub (at github.com) | 18:41 |
| litghost | kem_: Cool | 18:41 |
| litghost | kem_: If the stub detection code works, I could probably add a fixup pass in the meantime | 18:41 |
| litghost | kem_: The reason I detected this issue is I'm working on round tripping VPR output back into Vivado, and it was showing some routing pips no longer used, which I traced back to this antenna problem | 18:42 |
| litghost | kem_: Interesting!!!! Your route check failed on genfasm (e.g. loading route from file) but not on the original routing | 19:03 |
| litghost | kem_: This indicates to me there might be a bug in the router file output, rather than some other issue | 19:03 |
| litghost | kem_: Also worth noting that your stub check just segfaulted, rather than return an error :/ lol | 19:03 |
| litghost | kem_: We've been investigating some bugs in our designs, I wonder if these are route stubs at all, but partial route outputs that simply didn't get properly written to disk! | 19:05 |
| litghost | kem_: Sorry, I wonder if these are not stubs at all, but instead partial route outputs that simply didn't get properly written to disk! | 19:06 |
| litghost | kem_: Nevermind, the segfault was just a bug with the fact that rr_node_to_rt_node isn't allocated in analysis | 19:30 |
| litghost | kem_: And the stub check didn't find anything :( | 19:31 |
| litghost | kem_: I went back and double checked, and I think your commit doesn't handle configurable edges correctly. I think I have a commit that fixes that issue, and it does show a stub present | 22:08 |
| litghost | kem_: Handle non-configurable edges correctly | 22:08 |
| litghost | kem_: I think your previous code was conflating stub detection and error pruning | 22:13 |
| litghost | kem_: The new code always returns true for stubs, even if the stub was via a non-configurable edge | 22:13 |
| litghost | kem_: The error case IMO is child is a stub AND child was driven via a configurable edge | 22:14 |
| litghost | The previous code would never return true on non-configurable nodes because of "(child_is_stub && driver_switch_configurable) " | 22:15 |
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