Date: Thu, 12 May 2005 11:16:45 -0700
From: Tony Lindgren <tony@atomide.com>
To: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: vatsa@in.ibm.com, Lee Revell <rlrevell@joe-job.com>,
       Nick Piggin <nickpiggin@yahoo.com.au>, schwidefsky@de.ibm.com,
       jdike@addtoit.com, Ingo Molnar <mingo@elte.hu>,
       linux-kernel@vger.kernel.org, george@mvista.com
Subject: Re: [RFC] (How to) Let idle CPUs sleep
Message-ID: <20050512181644.GD15812@atomide.com>
References: <20050507182728.GA29592@in.ibm.com> <1115913679.20909.31.camel@mindpipe> <20050512161636.GA15653@atomide.com> <200505120928.55476.jesse.barnes@intel.com> <20050512171251.GA21656@in.ibm.com> <4283999F.8080609@virtuousgeek.org>
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* Jesse Barnes <jbarnes@virtuousgeek.org> [050512 11:01]:
> Srivatsa Vaddagiri wrote:
> 
> >Even if we were to go for this tickless design, the fundamental question
> >remains: who wakes up the (sleeping) idle CPU upon a imbalance? Does some 
> >other
> >(busy) CPU wake it up (which makes the implementation complex) or the idle 
> >CPU checks imbalance itself at periodic intervals (which restricts the 
> >amount of
> >time a idle CPU may sleep).
> > 
> >
> Waking it up at fork or exec time might be doable, and having a busy CPU 
> wake up other CPUs wouldn't add too much complexity, would it?

At least then it would be event driven rather than polling approach.

Tony
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