As I understand it, the kernel tests parity calc speed and decides to
use/not use mmx based on which is faster.
Assuming an otherwise heavily loaded cpu, would it not be better to use
mmx even though slightly slower just to free up cpu cycles for other tasks.
If I don't have the right picture here, someone please provide an
explaination of where the cpu cycles go to raid.
This reason for my question is the amount of "nice" cycles on one of my
machines that is fairly busy. Only raid5d is niced, and I'm running a
load factor over one consistently with only about a 20% cpu load. It
appears most of the cpu cycles in use go to raid5 -- presumably parity
calculations.
Assuming I'm not too far off base, it would be nice to have a /proc
option or at least a compile option to force use of mmx for raid parity
and a way to run the parity calculation test manually to see the difference
between the two methods.
Michael
