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Optimize Global Routing and Resizer PostGRT steps #538

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kareefardi opened this issue Aug 26, 2024 · 5 comments
Open

Optimize Global Routing and Resizer PostGRT steps #538

kareefardi opened this issue Aug 26, 2024 · 5 comments
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✨ enhancement New feature or request

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@kareefardi
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kareefardi commented Aug 26, 2024

Description

As it turns out estimating routing parasitics in OR needs a call for GRT in the same script (it cannot load all the info from the db). Some steps in the Classic flow use this. At the moment there are a lot of redundant GRT calls that slows down the flow in large designs.

Proposal

Access and revisit the situation. Additionally, GRT_RESIZER_RUN_GRT should only disable the final GRT step in the script. Finally, we should access incremental routing as well.

@kareefardi kareefardi added the ✨ enhancement New feature or request label Aug 26, 2024
@efabless efabless deleted a comment Aug 26, 2024
@donn
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donn commented Aug 26, 2024

Wasn't this addressed in a8a6e84

@donn donn added the 💬 waiting on op This issue requires more information from its original creator label Aug 26, 2024
@kareefardi kareefardi removed the 💬 waiting on op This issue requires more information from its original creator label Aug 26, 2024
@kareefardi
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Wasn't this addressed in a8a6e84

No. The solution is not complete and wrong given the current state of OR db.

@donn
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donn commented Aug 26, 2024

Elaborate.

@donn donn added the 💬 waiting on op This issue requires more information from its original creator label Aug 26, 2024
@kareefardi kareefardi removed the 💬 waiting on op This issue requires more information from its original creator label Aug 26, 2024
@kareefardi
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The solution doesn't consider other places in the flow that uses GRT parasitics estimation. It doesn't consider that there is a redundant GRT run before OpenROAD.RepairDesignPostGRT for example.
It is wrong because it turns out that GRT is needed in the same script as the ones modified in the PR. A similar PR should only disable GRT ran after calling resizer.

@donn
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donn commented Aug 26, 2024

If this is a Classic flow issue, not a step issue, that's a separate discussion. For the giant designs in question our PnR engineers tend to define custom sequential flows in the JSON…

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Labels
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