[PATCH] D128631: [AArch64] Initial sched model for Neoverse N2

Mon Jun 27 05:19:18 PDT 2022

c-rhodes added a comment.

In D128631#3611765 <https://reviews.llvm.org/D128631#3611765>, @dmgreen wrote:

> Hello - I've been looking at scheduling a little lately again. I presume this was created by transcribing the values from the Software Optimization guide? It looks nice and clean from what I  can see.

Hi Dave, that's right it's based on the optimization guide.

> I think we can use this new schedule for all "Arm-v9" cores in AArch64.td (that are not in-order). It will almost certainly be a better fit than the older A57 model, and be good to get some decent SVE information.

Sounds good, my only concern is we're quite keen to get this into LLVM 15 which branches around the middle of July I believe and making this the default for all v9 cores presumably raises the bar in terms of validating it is better than the A57 for the v9 cores?

> Can you take the tests from llvm/test/tools/llvm-mca/AArch64/Cortex/A55-basic-instructions.s and llvm/test/tools/llvm-mca/AArch64/Cortex/A55-neon-instructions.s and replicate them for the new model, and preferably find a way for writing a sve equivalent? We've found that those files make a great test of the information in the model.

I'll have a look.

Repository:
  rG LLVM Github Monorepo

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https://reviews.llvm.org/D128631