Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753318AbdGXI6B (ORCPT ); Mon, 24 Jul 2017 04:58:01 -0400 Received: from mail-pg0-f50.google.com ([74.125.83.50]:34223 "EHLO mail-pg0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752844AbdGXI5s (ORCPT ); Mon, 24 Jul 2017 04:57:48 -0400 Date: Mon, 24 Jul 2017 14:27:45 +0530 From: Viresh Kumar To: Joel Fernandes Cc: linux-kernel@vger.kernel.org, Juri Lelli , Patrick Bellasi , Andres Oportus , Dietmar Eggemann , linux-pm@vger.kernel.org, Srinivas Pandruvada , Len Brown , "Rafael J . Wysocki" , Ingo Molnar , Peter Zijlstra Subject: Re: [PATCH v7 1/2] cpufreq: schedutil: Make iowait boost more energy efficient Message-ID: <20170724085745.GU352@vireshk-i7> References: <20170723155426.9170-1-joelaf@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170723155426.9170-1-joelaf@google.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1869 Lines: 42 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 ? For both the patches: Acked-by: Viresh Kumar -- viresh