Re: 2.6.12-mm1 boot failure on NUMA box.

Martin J. Bligh
2005-06-28T22:18:03Z

--On Friday, June 24, 2005 19:01:12 +0200 Ingo Molnar <mingo@elte.hu> wrote:

>
> * Martin J. Bligh <mbligh@mbligh.org> wrote:
>
>> OK, still broken with the last 3 backed out, but works with the last 4
>> backed out. So I guess it's scheduler-cache-hot-autodetect.patch that
>> breaks it. Con just sent me something else to try to fix it in order
>> to run next ... will do that.
>
> hm. Does it work if you disable migration-autodetect via passing in e.g.
> migration_cost=1000,2000,3000 on the boot line? Is it perhaps the
> excessive debugging that hurts.
>
> or does it work if you undo the chunk below? Seemed harmless, but has
> CONFIG_NUMA relevance.

Sorry for slow response - had some problems with machines and the harness.
That didn't fix it, I'm afraid. I'll try to find some more time to beat
on the problem later.

M.

> Ingo
>
> --- linux/arch/i386/kernel/timers/timer_tsc.c.orig
> +++ linux/arch/i386/kernel/timers/timer_tsc.c
> @@ -133,18 +133,15 @@ static unsigned long long monotonic_cloc
>
> /*
> * Scheduler clock - returns current time in nanosec units.
> + *
> + * it's not a problem if the TSC is unsynchronized,
> + * as the scheduler will carefully compensate for it.
> */
> unsigned long long sched_clock(void)
> {
> unsigned long long this_offset;
>
> - /*
> - * In the NUMA case we dont use the TSC as they are not
> - * synchronized across all CPUs.
> - */
> -#ifndef CONFIG_NUMA
> - if (!use_tsc)
> -#endif
> + if (!cpu_has_tsc)
> /* no locking but a rare wrong value is not a big deal */
> return jiffies_64 * (1000000000 / HZ);
>
>
>
>