Re: Updated dynamic tick patches

From: Srivatsa Vaddagiri
Date: Thu Sep 01 2005 - 09:12:53 EST


On Thu, Sep 01, 2005 at 04:07:22PM +0300, Tony Lindgren wrote:
> I tried this quickly on a loaner ThinkPad T30, and needed the following
> patch to compile. The patch does work with PIT, but with lapic the
> system does not wake to timer interrupts :(

Even I have found that enabling lapic breaks it on my T30! I think
that is a T30 issue, as I dont see any other reason why it should not
work (note that I have it tested on some other SMP P4 servers where
it works well).

> I also hacked together a little timer test utility that should go trough
> on a completely idle system with no errors. Also posted it to:
>
> http://www.muru.com/linux/dyntick/tools/dyntick-test.c
>
> Srivatsa, could you try the dyntick-test.c on your system after booting
> to init=/bin/sh to make the system as idle as possible?

Thanks for this test. Will test and let you know how it goes on x86.
ATM I am trying to corner the lost-tick-calculation problem with ACPI
PM timer.

> Unfortunately I cannot debug the APIC issue right now, but I seem to
> have an issue on ARM OMAP where the timer test occasionally fails on
> some longer values, for example 3 second sleep can take 4 seconds.
>
> I don't know yet if this is the problem George Anzinger mentioned with
> next_timer_interrupt(), or if this is OMAP specific. But it only seems

Will let you know if I see it on x86 too.



--


Thanks and Regards,
Srivatsa Vaddagiri,
Linux Technology Center,
IBM Software Labs,
Bangalore, INDIA - 560017
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/