linux-kernel - Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle)

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Message-ID: <alpine.DEB.2.20.1601261025320.27957@east.gentwo.org>
Date:	Tue, 26 Jan 2016 10:26:04 -0600 (CST)
From:	Christoph Lameter <cl@...ux.com>
To:	Mike Galbraith <umgwanakikbuti@...il.com>
cc:	Michal Hocko <mhocko@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable
 again and shut down on idle)

On Tue, 26 Jan 2016, Mike Galbraith wrote:

> > Why would the deferring cause this overhead?
>
> Because we schedule to idle cores aggressively, thus we may pop in and
> out of idle at high frequency.

Whats the point of going idle if you have things to do soon?