RE: Add prefetch switch stack hook in scheduler function

Chen, Kenneth W
2005-07-29T08:08:48Z

Keith Owens wrote on Friday, July 29, 2005 12:38 AM
> BTW, for ia64 you may as well prefetch pt_regs, that is also quite
> large.
>
> #define MIN_KERNEL_STACK_FOOTPRINT (IA64_SWITCH_STACK_SIZE + IA64_PT_REGS_SIZE)

This has to be carefully done, because you really don't want to overwhelm
number of outstanding L2 cache misses. It only has a limited amount of
queue and once that is filled, cpu get into L2 recirculate state. And that
is going to be very painful because it translate into cpu stall cycles.