RVC by default?

[Vladimir Kempik]

Hello

When doing some benchmarks on risc-v cores, I have observed slight performance decrease when RVC is enabled ( for example in renaissance philosophers)

Regards, Vladimir

> 8 сент. 2022 г., в 13:33, Aleksey Shipilev <shade at redhat.com> написал(а):
> 
> Hi,
> 
> I was looking at some generated code on RISC-V, and realized while we have RVC support, we don't enable it by default. On HiFive Unleashed:
> 
> $ test-jdk/bin/java -XX:+UnlockExperimentalVMOptions -XX:+PrintFlagsFinal 2>&1 | grep RVC
>     bool UseRVC                                   = false                           {ARCH experimental} {default}
> 
> 
> Is there a reason not to do RVC by default? Can we reliably poll the RVC capabilities in current hardware?
> 
> -- 
> Thanks,
> -Aleksey
>