[PATCH] x86_64: Allow to run main time keeping from the local APIC interrupt
authorAndi Kleen <ak@suse.de>
Fri, 3 Feb 2006 20:50:50 +0000 (21:50 +0100)
committerLinus Torvalds <torvalds@g5.osdl.org>
Sun, 5 Feb 2006 00:43:13 +0000 (16:43 -0800)
commit73dea47faeb96d54a984b9d7f4de564816966354
tree6b1f090e9071e281367bc106c1b2ab05cb43e459
parent76b461c21468f41837283b7888d55f1c0671f719
[PATCH] x86_64: Allow to run main time keeping from the local APIC interrupt

Another piece from the no-idle-tick patch.

This can be enabled with the "apicmaintimer" option.

This is mainly useful when the PIT/HPET interrupt is unreliable.
Note there are some systems that are known to stop the APIC
timer in C3. For those it will never work, but this case
should be automatically detected.

It also only works with PM timer right now. When HPET is used
the way the main timer handler computes the delay doesn't work.

It should be a bit more efficient because there is one less
regular interrupt to process on the boot processor.

Requires earlier bugfix from Venkatesh

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Documentation/x86_64/boot-options.txt
arch/x86_64/kernel/apic.c
arch/x86_64/kernel/time.c
include/asm-x86_64/apic.h
include/asm-x86_64/proto.h