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by nemonemo 567 days ago
Thank you for your thoughtful response. Acknowledging potential biases openly in a public forum is never easy, and in my view, it adds credibility to your words compared to leaving such matters as implicit insinuations.

That said, on page 8, the paper says that 'standard licensing agreements with commercial vendors prohibit public comparison with their offerings.' Given this inherent limitation, what alternative approach could have been taken to enable a more meaningful comparison between CT and CMP?

1 comments

So I'm not sure what Google is referring to here. As you can see in the ISPD paper (https://vlsicad.ucsd.edu/Publications/Conferences/396/c396.p...) on page 5, they openly compare Cadence CMP with AutoDMP and other algorithims quantitatively. The only obfuscation is with the proprietary GF12 technology, where they can't provide absolute numbers, but only relative ones. Comparison against commercial tools is actually a common practice in academic EDA CAD papers, although usually the exact tool vendor is obfuscated. CAD tool vendors have actually gotten more permissive about sharing tool data and scripts in public over the past few years. However, PDKs have always been under NDAs and are still very restrictive.

Perhaps the Cadence license agreement signed by a corporation is different than the one signed by a university. In such a case, they could partner with a university. But I doubt their license agreement prevents any public comparison. For example, see the AutoDMP paper from NVIDIA (https://d1qx31qr3h6wln.cloudfront.net/publications/AutoDMP.p...) where on page 7 they openly benchmark their tool against Cadence Innovus. My suspicion is they wish to keep details about the TPU blocks they evaluated under tight wraps.

The UCSD paper says "We thank ... colleagues at Cadence and Synopsys for policy changes that permit our methods and results to be reproducible and sharable in the open, toward advancement of research in the field." This suggests that there may have been policies restricting publication prior to this work. It would be intriguing to see if future research on AlphaChip could receive a similar endorsement or support from these EDA companies.
Cadence in particular has been quite receptive to allowing academics and researchers to benchmark new algorithms against their tools. They have also been quite permissive with letting people publish TCL scripts for their tools (https://github.com/TILOS-AI-Institute/MacroPlacement/tree/ma...) that in theory should enable precise reproduction of results. From my knowledge, Cadence has been very permissive from 2022 onwards, so while Google's objections to publishing data from CMP may have been valid when the Nature paper was published, they are no longer valid today.
We're not just talking about academia—Google's AlphaChip has the potential to disrupt the balance of the EDA industry's duopoly. It seems unlikely that Google could easily secure the policy or license changes necessary to publish direct comparisons in this context.

If publicizing comparisons of CMPs is as permissible as you suggest, have you seen a publication that directly compares a Cadence macro placement tool with a Synopsys tool? If I were the technically superior party, I’d be eager to showcase the fairest possible comparison, complete with transparent benchmarks and tools. In the CPU design space, we often see standardized benchmarking tools like SPEC microbenchmarks and gaming benchmarks. (And IMO that's part of why AMD could disrupt the PC market.) Does the EDA ecosystem support a similarly open culture of benchmarking for commercial tools?

> Does the EDA ecosystem support a similarly open culture of benchmarking for commercial tools?

If only. The comparison in Cheng et al. is the only public comparison with CMP that I can recall, and it is pretty suss that this just so happens to be a very pro-commercial-autoplacer study. (And, Cheng et al. have cited 'licensing agreements' as a reason for not giving out the synthesized netlists necessary to reproduce their results.)

Reminded a bit of Oracle. They likewise used to (and maybe still?) prohibit any benchmarking of their database software against that of another provider. This seems to be a common move for solidifying a strong market position.

I am trying to understand what you mean here by potential to disrupt. AlphaChip addresses one out of hundreds of tasks in chip design. Macro placement is a part of mixed-size placement, which is handled just fine by existing tools, many academic tools, open-source tools, and Nvidia AutoDMP. Even if AlphaChip was commonly accepted as a breakthrough, there is no disruption here. Direct comparisons from the last 3 years show that AlphaChip is worse. Granted, Google is belittling these comparisons, but that's what you'd expect. In any case, evidence is evidence.
> Direct comparisons from the last 3 years show that AlphaChip is worse.

Do you have any evidence to claim this? The whole point of this thread is that the direct comparisons might have been insufficient, and even the author of "The Saga" article who's biased against the AlphaChip work agreed.

> Granted, Google is belittling these comparisons, but that's what you'd expect.

This kind of language doesn't help any position you want to advocate.

About "the potential to disrupt", a potential is a potential. It's an initial work. What I find interesting is that people are so eager to assert that it's a dead-end without sufficient exploration.