kozman wrote: ↑
Tue Oct 30, 2018 4:20 pm
Very interesting results I must say. Can Raspbian be tweaked the same way?
ARMv7 optimized versions of the kernel are already used in Raspbian when an ARMv7 capable CPU is detected. However, most of Raspbian userland is compiled for ARMv6 with the notable exception of some libraries. This is to ensure compatibility of the same SD card across all models of Pi computers in educational contexts where children and teachers are swapping cards between Pi computers on a per user or per project basis. While a fully-optimized ARMv7 distribution will likely be faster, this is a bit off topic for this thread.
At this point you may wonder about having an ARMv8 optimized kernel. I think running the CPU in 64-bit mode may slow down communication with the VC4 GPU. Others may comment on this with more details. Still, some programs in userland run faster in 64-bit mode. At the same time, increased memory and memory bandwidth contention can also slow things down. Therefore, each executable would have to be examined on a case by case basis to know which version is preferable and that might change depending on how much memory pressure the system is currently experiencing. Again this is a bit off topic for this thread.