From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755234AbdESJmz (ORCPT ); Fri, 19 May 2017 05:42:55 -0400 Received: from bombadil.infradead.org ([65.50.211.133]:54791 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750943AbdESJmv (ORCPT ); Fri, 19 May 2017 05:42:51 -0400 Date: Fri, 19 May 2017 11:42:45 +0200 From: Peter Zijlstra To: Joel Fernandes Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, Srinivas Pandruvada , Len Brown , "Rafael J . Wysocki" , Viresh Kumar , Ingo Molnar Subject: Re: [PATCH v2 1/2] cpufreq: Make iowait boost a policy option Message-ID: <20170519094245.ztm6tt2iwkaiwsya@hirez.programming.kicks-ass.net> References: <20170519062344.27692-1-joelaf@google.com> <20170519062344.27692-2-joelaf@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170519062344.27692-2-joelaf@google.com> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 18, 2017 at 11:23:43PM -0700, Joel Fernandes wrote: > Make iowait boost a cpufreq policy option and enable it for intel_pstate > cpufreq driver. Governors like schedutil can use it to determine if > boosting for tasks that wake up with p->in_iowait set is needed. Rather than just flat out disabling the option, is there something better we can do on ARM? The reason for the IO-wait boost is to ensure we feed our external devices data ASAP, this reduces wait times, increases throughput and decreases the duration the devices have to operate. I realize max freq/volt might not be the best option for you, but is there another spot that would make sense? I can imagine you want to return your MMC to low power state ASAP as well. So rather than a disable flag, I would really rather see an IO-wait OPP state selector or something.