For those who don't know the libcofi was a small library that had hand optimized
assembly version of 2 libc functions that could speed applications using those
functions a lot, when set to be preloaded.
Libcofi has now been superseded by arm-mem, it provided more hand optimized
functions and is also faster. This is included in raspbian by default, so make sure
to install this, it would be shame to have slower performance on Arch compared to
Debian...
https://github.com/bavison/arm-mem
AUR: https://aur.archlinux.org/packages/arm-mem-git/
Install it and reboot. All applications using lots of memX functions should see a nice
increase in performance.