Hi, On 27 August 2018 at 16:13, Andrew Haley <a...@redhat.com> wrote: > 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. >
Yes, some benchmark data is unstable. We did analyze the arm64 and aarch64 codegen difference with microbenchmarks. AArch64 backend generates better code on most cases, and I believe that we have addressed those minor worse cases we found. E.g. JDK-8183533, JDK-8185786, JDK-8187601. Thanks, Ningsheng