On Fri, 3 Oct 2008, Alan Stern wrote:
quoted text
> On Fri, 3 Oct 2008, Dave Hansen wrote:
> There are a number of other places in the trace where delays are
> shorter than they should be.  This is out of my area of expertise, so 
> I'm CC'ing Thomas Gleixner.  With luck he'll be able to help.
> 
> Thomas, the background for this problem is available here:
> 
> 	http://marc.info/?l=linux-kernel&m=122305738430115&w=2

Is NOHZ and HIGHRES disabled on those kernels? Hugh spotted a typo in
that code today. Fix is below. It causes jiffies to increment too fast
which explains your short delays.

Thanks,

	tglx
---
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index bd70345..cb01cd8 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -235,7 +235,8 @@ static void tick_do_broadcast_on_off(void *why)
 	case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
 		if (!cpu_isset(cpu, tick_broadcast_mask)) {
 			cpu_set(cpu, tick_broadcast_mask);
-			if (bc->mode == TICKDEV_MODE_PERIODIC)
+			if (tick_broadcast_device.mode ==
+			    TICKDEV_MODE_PERIODIC)
 				clockevents_shutdown(dev);
 		}
 		if (*reason == CLOCK_EVT_NOTIFY_BROADCAST_FORCE)
@@ -245,7 +246,8 @@ static void tick_do_broadcast_on_off(void *why)
 		if (!tick_broadcast_force &&
 		    cpu_isset(cpu, tick_broadcast_mask)) {
 			cpu_clear(cpu, tick_broadcast_mask);
-			if (bc->mode == TICKDEV_MODE_PERIODIC)
+			if (tick_broadcast_device.mode ==
+			    TICKDEV_MODE_PERIODIC)
 				tick_setup_periodic(dev, 0);
 		}
 		break;


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