Messages in this thread | | | Date | Tue, 4 Nov 2003 15:52:14 -0500 | Subject | Re: [PATCH] amd76x_pm on 2.6.0-test9 cleanup | From | Charles Lepple <> |
| |
On Tuesday, November 4, 2003, at 03:05 PM, Tony Lindgren wrote:
> * Charles Lepple <clepple@ghz.cc> [031104 11:45]: >> On Tuesday 04 November 2003 02:15 pm, Tony Lindgren wrote: >>> I've heard of timing problems if it's compiled in, but supposedly >>> they >>> don't happen when loaded as module. >> >> In some of the earlier testX versions of the kernel, I did not see any >> difference between compiling as a module, and compiling into the >> kernel. (It >> is currently a module on my system.) >> >> I did, however, manage to keep ntpd happy by reducing HZ to 100. Even >> raising >> HZ to 200 is enough to throw off its PLL. The machine is idle for 90% >> of the >> day, though, so I don't know if the PLL is adapting to the fact that >> the >> system is idling, but the values for tick look reasonable. > > Interesting, sounds like the idling causes missed timer interrupts? > Can you > briefly describe what's the easiest way to reproduce the timer > problem, just > change HZ to 200 and look at the system time?
At HZ=200, it would take a while to notice. I used adjtimexconfig, which counts the number of kernel ticks which occur in 70 seconds (according to the RTC). The RTC is pretty stable without power management, so I tend to trust it. I think I ended up with a value of tick=11000 (compensation for a 10% slow clock), and if I left the machine idle, ntpd would converge based on the new tick value.
Then again, I don't think I tried HZ>=200 on -test9. (When I got Pasi's -test9 patch, I applied it to a -test8-bk kernel with HZ=1000-- I don't remember exactly which one.) Based on his followup email, timekeeping may be better in -test9. I'll check.
> I've been using kexec for reboots recently though as the bios reboot > is soo slow.
The slowness on my system is supposedly related to ECC initialization, but it's only ~30 seconds for 512MB. Still, if I upgrade the memory, that's a good tip.
> But just to verify: 2.6.0-test9 & amd76x_pm as module, and the system > drops > into sleep mode when the module is loaded for the first time until > power is > pressed? And this does not happen after cold reboots or when the > amd76x_pm > is reloaded?
Correct.
-- Charles Lepple clepple@ghz.cc
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |