[PATCH] D152417: [AArch64] Add pipeline model for Neoverse N1

[Evandro Menezes via Phabricator via llvm-commits]

evandro added a comment.

@dmgreen,

> Thanks. Is that speed or time? I assume speed so higher is better?

Correct.

> I'm just asking because I had tested on the Noeverse-N1 hardware we have as it is easy to run. It has been fairly well setup to minimize noise, and noticed a higher time on x264 then I would have expected. It has reproduced multiple times, but there is a chance that it is just what I would call "layout noise", and the same code with slightly different options would give different results. If you don't see the same thing then it is probably OK. The other results all looked fine, all plus or minus a percent. The change in lbm I saw was smaller, for example, only 0.9%.

I can say that I see a consistent improvement of about 1% or a couple of seconds in x264 with this patch.  With regards to lbm, I'm being pessimistic above, as I often see a slow down of about 1%.  There is a bit of "layout noise" (I'm borrowing it!) and nothing jumps to attention to explain the difference.

PS: I'd love to get the recipe to minimize system noise.


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  https://reviews.llvm.org/D152417/new/

https://reviews.llvm.org/D152417