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From: Andi Kleen <ak@suse.de>
To: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	manfred@colorfullife.com
Subject: Re: Weird schedule delay time for cache_reap()
Date: Thu, 27 Oct 2005 10:37:08 +0200	[thread overview]
Message-ID: <200510271037.08853.ak@suse.de> (raw)
In-Reply-To: <200510270228.j9R2SWg27777@unix-os.sc.intel.com>

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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      reply	other threads:[~2005-10-27  8:37 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-10-27  2:28 Chen, Kenneth W
2005-10-27  8:37 ` Andi Kleen [this message]

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