Re: 2.6.12-mm1 boot failure on NUMA box.

["Martin J. Bligh" <mbligh@mbligh.org>]

--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);
>  
> 
> 
> 


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