Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932482AbdGXSiF (ORCPT ); Mon, 24 Jul 2017 14:38:05 -0400 Received: from mail-oi0-f44.google.com ([209.85.218.44]:34004 "EHLO mail-oi0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932195AbdGXSh7 (ORCPT ); Mon, 24 Jul 2017 14:37:59 -0400 MIME-Version: 1.0 In-Reply-To: <20170724085745.GU352@vireshk-i7> References: <20170723155426.9170-1-joelaf@google.com> <20170724085745.GU352@vireshk-i7> From: Joel Fernandes Date: Mon, 24 Jul 2017 11:37:58 -0700 Message-ID: Subject: Re: [PATCH v7 1/2] cpufreq: schedutil: Make iowait boost more energy efficient To: Viresh Kumar Cc: LKML , Juri Lelli , Patrick Bellasi , Andres Oportus , Dietmar Eggemann , Linux PM , Srinivas Pandruvada , Len Brown , "Rafael J . Wysocki" , Ingo Molnar , Peter Zijlstra Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2083 Lines: 48 On Mon, Jul 24, 2017 at 1:57 AM, Viresh Kumar wrote: > On 23-07-17, 08:54, Joel Fernandes wrote: >> Currently the iowait_boost feature in schedutil makes the frequency go to max >> on iowait wakeups. This feature was added to handle a case that Peter >> described where the throughput of operations involving continuous I/O requests >> [1] is reduced due to running at a lower frequency, however the lower >> throughput itself causes utilization to be low and hence causing frequency to >> be low hence its "stuck". >> >> Instead of going to max, its also possible to achieve the same effect by >> ramping up to max if there are repeated in_iowait wakeups happening. This patch >> is an attempt to do that. We start from a lower frequency (policy->min) >> and double the boost for every consecutive iowait update until we reach the >> maximum iowait boost frequency (iowait_boost_max). >> >> I ran a synthetic test (continuous O_DIRECT writes in a loop) on an x86 machine >> with intel_pstate in passive mode using schedutil. In this test the iowait_boost >> value ramped from 800MHz to 4GHz in 60ms. The patch achieves the desired improved >> throughput as the existing behavior. >> >> [1] https://patchwork.kernel.org/patch/9735885/ >> >> Cc: Srinivas Pandruvada >> Cc: Len Brown >> Cc: Rafael J. Wysocki >> Cc: Viresh Kumar >> Cc: Ingo Molnar >> Cc: Peter Zijlstra >> Suggested-by: Peter Zijlstra >> Suggested-by: Viresh Kumar >> Signed-off-by: Joel Fernandes >> --- >> kernel/sched/cpufreq_schedutil.c | 38 ++++++++++++++++++++++++++++++++------ >> 1 file changed, 32 insertions(+), 6 deletions(-) > > You Send V7 [1-2]/2 twice, Are they different ? No they are the same. Rafael suggested reposting it with linux-pm in CC I just resent it. > > For both the patches: > > Acked-by: Viresh Kumar Thanks! -Joel