Messages in this thread | | | Date | Tue, 4 Nov 2003 17:38:33 -0500 | Subject | Re: [PATCH] amd76x_pm on 2.6.0-test9 cleanup | From | Charles Lepple <> |
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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?
Weird. On -test9-bk at HZ=1000, with amd76x_pm loaded as a module (lazy_idle=800, the default), the system clock is running fast.
With ntpd running, the clock was stepped back 2.5 seconds twice in 20 minutes.
Here's what I get from adjtimexconfig (after stopping ntpd, of course):
# adjtimexconfig Comparing clocks (this will take 70 sec)... adjusting system time by -126.211 sec/day Done
Now tick is 9985. I distinctly remember it being somewhat over 10,000 the last time I ran with HZ=1000 and amd_76x_pm active. With HZ=100, adjtimexconfig sets tick=10002.
I'm not entirely sure what the "acpi" interrupt is doing-- it increments about once every two seconds when the system is idle, and various types of system activity make it happen more frequently. At least I'm not getting any "irq 9: nobody cared!" messages anymore (the button module is loaded, so I guess it is handling it). If I don't have amd76x_pm loaded, the acpi interrupt is triggered a couple of times after button is loaded, but then it doesn't happen again until I actually press a button.
-- Charles Lepple ghz.cc! clepple
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