mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
* [PATCH 14/19] UML - Fix bad NTP interaction with clock
@ 2008-04-25 17:56 Jeff Dike
  0 siblings, 0 replies; only message in thread
From: Jeff Dike @ 2008-04-25 17:56 UTC (permalink / raw)
  To: Andrew Morton, LKML, uml-devel; +Cc: Ryan Finnie

UML's supposed nanosecond clock interacts badly with NTP when NTP
decides that the clock has drifted ahead and needs to be slowed down.
Slowing down the clock is done by decrementing the cycle-to-nanosecond
multiplier, which is 1.  Decrementing that gives you 0 and time is
stopped.

This is fixed by switching to a microsecond clock, with a multiplier
of 1000.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
---
 arch/um/kernel/time.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Index: linux-2.6-git/arch/um/kernel/time.c
===================================================================
--- linux-2.6-git.orig/arch/um/kernel/time.c	2008-02-15 11:43:41.000000000 -0500
+++ linux-2.6-git/arch/um/kernel/time.c	2008-04-24 16:01:35.000000000 -0400
@@ -74,7 +74,7 @@ static irqreturn_t um_timer(int irq, voi
 
 static cycle_t itimer_read(void)
 {
-	return os_nsecs();
+	return os_nsecs() / 1000;
 }
 
 static struct clocksource itimer_clocksource = {
@@ -82,7 +82,7 @@ static struct clocksource itimer_clockso
 	.rating		= 300,
 	.read		= itimer_read,
 	.mask		= CLOCKSOURCE_MASK(64),
-	.mult		= 1,
+	.mult		= 1000,
 	.shift		= 0,
 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 };

^ permalink raw reply	[flat|nested] only message in thread

only message in thread, other threads:[~2008-04-25 18:01 UTC | newest]

Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2008-04-25 17:56 [PATCH 14/19] UML - Fix bad NTP interaction with clock Jeff Dike

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox

all inboxes | Powered by JetHome®