[parisc-linux] itlb miss handler optimizations!

[Carlos O'Donell]

> Well I finaly find it on sf.net (via osdl.org)
> And submit some bench which seems to be more in relation with vm (?):
> ./reaim -x -t -f worfile.shared -r3

Thanks for that run Joel, I'll take a look at the numbers in a few
minutes. Adding to that here is the lmbench results (urls) for both
the non-optimized and optimized cases of the itlb fault handler.

It seems that some things got faster, or rather more predictably fast
within the confidence levels (e.g. number of tests that I ran).

I ran 10 lmbench run's for each of the two kernels and then munged them
using the stat-summary script provided with lmbench. Do the diff to see
the numbers change :)

Looks like we have better performance in many places.

null call, null i/o, stat, open/close, select, signal install, signal
catch, exec, shell proc, (a variety of the process spawning tests),
create, delete, mmap latency, page fault (way down! and deterministic)
-- All got better with itlb branch prediction optimization

Please give it a double check to make sure I'm not out of it this
morning.

http://www.baldric.uwo.ca/~carlos/itlb-opt.txt
http://www.baldric.uwo.ca/~carlos/no-itlb-opt.txt

c.