[patch] Lowlatency Patch for 2.4.0-ac6 and 2.4.1-pre2

[Ingo Molnar]

a new version against recent 2.4 kernels of my multimedia-lowlatency
patchset is now available. These patches are the 2.4-adapted versions of
my 2.2 lowlatency patch, which project has now reached an age of 1.5+
years.

the lowlatency patch against 2.4.0-ac6 can also be found at:

   http://www.kernel.org/pub/linux/kernel/people/mingo/lowlatency-patches/lowlatency-2.4.0-ac6-A2

the lowlatency patch against 2.4.1-pre2 can be found at:

   http://www.kernel.org/pub/linux/kernel/people/mingo/lowlatency-patches/lowlatency-2.4.1-A2

this patch still follows the 'take no prisoners' approach, is optimized on
x86 but should work on other platforms as well. The patch uses assembly
speedups and offline assembly sections to minimize the impact of
conditional schedule points as much as possible. This is the reason why
this patch does not offer a configuration option. The patch changes
lowlevel x86 assembly routines too, to make them perform with lower
latency.

on a 500 MHz 1-CPU box typical latencies during 'everyday work', with this
patch applied are 0.1 msec or less, under high load i've measured a
maximum latency was 0.3 millisec. The patch fixes latencies generated by
intense X sessions, high block IO and networking load and lots of
user-space processes load as well, and other more unusual latency sources.
I tested every latency source i could think of, the patch tries to be a
'complete solution' and tries to squash all latency sources larger than
0.5 msecs on a typical system.

bugreports, comments, suggestions and contributions welcome!

	Ingo