From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arjan van de Ven Subject: Re: [PATCH 2/3] cpuidle,menu: use interactivity_req to disable polling Date: Wed, 4 Nov 2015 08:01:38 -0800 Message-ID: <563A2BE2.4090101@linux.intel.com> References: <1446590059-18897-1-git-send-email-riel@redhat.com> <1446590059-18897-3-git-send-email-riel@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mga14.intel.com ([192.55.52.115]:27765 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964926AbbKDQBv (ORCPT ); Wed, 4 Nov 2015 11:01:51 -0500 In-Reply-To: <1446590059-18897-3-git-send-email-riel@redhat.com> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: riel@redhat.com, linux-pm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, rafael.j.wysocki@intel.com, len.brown@intel.com, daniel.lezcano@linaro.org On 11/3/2015 2:34 PM, riel@redhat.com wrote: > From: Rik van Riel > > The menu governor carefully figures out how much time we typically > sleep for an estimated sleep interval, or whether there is a repeating > pattern going on, and corrects that estimate for the CPU load. > > Then it proceeds to ignore that information when determining whether > or not to consider polling. This is not a big deal on most x86 CPUs, > which have very low C1 latencies, and the patch should not have any > effect on those CPUs. > > However, certain CPUs (eg. Atom) have much higher C1 latencies, and > it would be good to not waste performance and power on those CPUs if > we are expecting a very low wakeup latency. > > Disable polling based on the estimated interactivity requirement, not > on the time to the next timer interrupt. > good catch! Acked-by: Arjan van de Ven