On Monday 25 January 2010, Shawn Starr wrote: > On Monday 25 January 2010 12:20:38 Thomas Gleixner wrote: > > On Mon, 25 Jan 2010, Shawn Starr wrote: > > > On Monday 25 January 2010 05:35:50 Thomas Gleixner wrote: > > > > Shawn, why can't you use dynamic ticks ? In the bugzilla I just see > > > > that you worry about the IRQ0 interrupts (which are correct and > > > > necessary when the system is in nohz mode) and the extra rescheduling > > > > interrupts. How is the system misbehaving ? > > > > > > Well, this all stems from trying to use Radeon KMS with IRQs > > > on. Doing so I see system stalls and this is quite noticeable > > > however, I am able to show this same stall on the quad core with the > > > > x> same GPU. Right now, it is unclear to me if there is a underlying > > > > > irq issue or a bug in the radeon driver code that is showing these > > > stalls. Since the radeon folks - at the moment - do not think it is > > > a coding problem in their driver > > > > Does the stall go away, when you disable dynticks ? > > > > It does not, no. > > > > My impression was using dynamic ticks meant ticks were on demand and > > > > Dynamic ticks are providing a continuous tick long as the machine is > > busy. When a core becomes idle, we programm the timer to go off at the > > next scheduled timer event, if the event is longer away than the next > > tick. When the core goes out of idle (due to the timer or some other > > event) we restart the tick. > > > > So you see less timer interrupts (IRQ0 + Local timer interrupts) > > With dynamic ticks on or off, LOC increments rapidly, but I assume that is > normal behavour. > > So if none of this really is a kernel issue, I defer it to the radeon folks > to > comment further. > > Please remove from regression list, I'll close the original bug.
OK, closing it right now. Rafael -- To unsubscribe from this list: send the line "unsubscribe kernel-testers" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
