From: Andi Kleen <ak@suse.de>
To: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
Subject: Re: Weird schedule delay time for cache_reap()
Date: Thu, 27 Oct 2005 10:37:08 +0200
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On Thursday 27 October 2005 04:28, Chen, Kenneth W wrote:
> can't convince myself that the 2nd argument in schedule_delayed_work
>called from cache_reap() function make any sense:


>static void cache_reap(void *unused)
>{ ...
>schedule_delayed_work(&__get_cpu_var(reap_work), REAPTIMEOUT_CPUC + 
smp_processor_id());
>
> Suppose one have a lucky 1024-processor big iron numa box,
> cpu0 will do cache_reap every 2 sec (REAPTIMEOUT_CPUC = 2*HZ).
> cpu512 will do cache_reap every 4 sec,
> cpu1023 will do cache_reap every 6 sec.
>
> Is the skew intentional on different CPU?  Why different interval for
> different cpu#?

It looks like a buggy attempt to make the timers not cluster.
The +smp_processor_id() should be probably only done on the first iteration.
start_cpu_timer() does this already, so removing it should be ok.

-Andi
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