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authorAndi Kleen <ak@suse.de>2006-02-03 21:50:50 +0100
committerLinus Torvalds <torvalds@g5.osdl.org>2006-02-04 16:43:13 -0800
commit73dea47faeb96d54a984b9d7f4de564816966354 (patch)
tree6b1f090e9071e281367bc106c1b2ab05cb43e459 /Documentation/x86_64
parent76b461c21468f41837283b7888d55f1c0671f719 (diff)
downloadlinux-73dea47faeb96d54a984b9d7f4de564816966354.tar.bz2
[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>
Diffstat (limited to 'Documentation/x86_64')
-rw-r--r--Documentation/x86_64/boot-options.txt7
1 files changed, 7 insertions, 0 deletions
diff --git a/Documentation/x86_64/boot-options.txt b/Documentation/x86_64/boot-options.txt
index 9c5fc15d03d1..654ea4fccff8 100644
--- a/Documentation/x86_64/boot-options.txt
+++ b/Documentation/x86_64/boot-options.txt
@@ -40,6 +40,13 @@ APICs
no_timer_check Don't check the IO-APIC timer. This can work around
problems with incorrect timer initialization on some boards.
+ apicmaintimer Run time keeping from the local APIC timer instead
+ of using the PIT/HPET interrupt for this. This is useful
+ when the PIT/HPET interrupts are unreliable.
+
+ noapicmaintimer Don't do time keeping using the APIC timer.
+ Useful when this option was auto selected, but doesn't work.
+
Early Console
syntax: earlyprintk=vga