Message-ID: <42553E7E.8000102@yahoo.com.au>
Date: Fri, 08 Apr 2005 00:06:54 +1000
From: Nick Piggin <nickpiggin@yahoo.com.au>
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To: vatsa@in.ibm.com
CC: george@mvista.com, mingo@elte.hu,
       high-res-timers-discourse@lists.sourceforge.net,
       linux-kernel@vger.kernel.org
Subject: Re: VST and Sched Load Balance
References: <20050407124629.GA17268@in.ibm.com> <425530AB.90605@yahoo.com.au> <20050407140040.GD17268@in.ibm.com>
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Srivatsa Vaddagiri wrote:

> 
> Hmm ..I guess we could restrict the max time a idle CPU will sleep taking
> into account its balance interval. But whatever heuristics we follow to 
> maximize balance_interval of about-to-sleep idle CPU, don't we still run the 
> risk of idle cpu being woken up and going immediately back to sleep (because 
> there was no imbalance)?
> 

Yep.

> Moreover we may be greatly reducing the amount of time a CPU is allowed to 
> sleep this way ...
> 

Yes. I was assuming you get some kind of fairly rapidly diminishing
efficiency return curve based on your maximum sleep time. If that is
not so, then I agree this wouldn't be the best method.

-- 
SUSE Labs, Novell Inc.

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