[aarch64-port-dev ] RFC: JEP - One AArch64 Port, Not Two

[Andrew Haley]

On 08/27/2018 07:30 AM, Magnus Ihse Bursie wrote:
> One question: I remember there were some guys from Linaro who compared 
> aarch64 vs arm64 in microbenchmarks, and found that while aarch64 had 
> the superior performance most of the time, there were some benchmarks 
> where arm64 was fastest.
> 
> Has these been analyzed, and the performance on aarch64 brought in line 
> with arm64?

I doubt that's possible. As we know, JIT heuristics can sometimes go one
way and then the other, and it can be just a matter of luck. I haven't
seen any optimizations in the arm64 port that were absent in the aarch64
port. If anyone can find anything we'll port it over.

Looking here

https://docs.google.com/spreadsheets/d/18iklOrbaL67i46XHsPTrdTObWqUJJK8EO4-k0eqdLKM/edit#gid=909743165

we see that tradebeans is faster on one implementation, slower on another.
sunflow is spectacularly better on arm64, but it failed to converge most
of the time on one implementation, so I don't believe the result.

-- 
Andrew Haley
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
EAC8 43EB D3EF DB98 CC77 2FAD A5CD 6035 332F A671