On Fri, Jan 12, 2024 at 5:07 PM Alan Corey <[email protected]> wrote: > > So, can you set an RPI4 to 32 bit for even more speed? > My Pi4 config.txt (Debian Bookworm) says > > # Switch the CPU from ARMv7 into ARMv8 (aarch64) mode > arm_64bit=1 >
You would have to try it to see if it is faster for your workload. I suspect that the context switch is faster because there are fewer registers to save/restore and they are 32 bit vs. 64 bit. Addresses are also 32 bit, requiring less to load from RAM. (And I am not familiar with ARM addressing modes so there may well be relative addresses that allow shorter addresses in 64 bit mode.) I also wonder about differences in CPU cache between 32 and 64 bit mode. Some of these things slow specific operations while others (such as more registers) can improve performance. There's probably other stuff I'm not aware of that affects performance comparisons between 64 and 32 bit mode. -- Beautiful Sunny Winfield
