From patchwork Wed Jan 22 17:35:37 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Douglas RAILLARD X-Patchwork-Id: 11346155 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8D2ED139A for ; Wed, 22 Jan 2020 17:36:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 75EB62467B for ; Wed, 22 Jan 2020 17:36:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726968AbgAVRgY (ORCPT ); Wed, 22 Jan 2020 12:36:24 -0500 Received: from foss.arm.com ([217.140.110.172]:59050 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729239AbgAVRgT (ORCPT ); Wed, 22 Jan 2020 12:36:19 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 7ABA011FB; Wed, 22 Jan 2020 09:36:18 -0800 (PST) Received: from e107049-lin.arm.com (e107049-lin.cambridge.arm.com [10.1.195.43]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 2B9493F6C4; Wed, 22 Jan 2020 09:36:17 -0800 (PST) From: Douglas RAILLARD To: linux-kernel@vger.kernel.org, rjw@rjwysocki.net, viresh.kumar@linaro.org, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org Cc: douglas.raillard@arm.com, dietmar.eggemann@arm.com, qperret@google.com, linux-pm@vger.kernel.org Subject: [RFC PATCH v4 5/6] sched/cpufreq: Boost schedutil frequency ramp up Date: Wed, 22 Jan 2020 17:35:37 +0000 Message-Id: <20200122173538.1142069-6-douglas.raillard@arm.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200122173538.1142069-1-douglas.raillard@arm.com> References: <20200122173538.1142069-1-douglas.raillard@arm.com> MIME-Version: 1.0 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org In some situations, it can be interesting to spend temporarily more power if that can give a useful frequency boost. Use the new sugov_cpu_ramp_boost() function to drive an energy-aware boost, on top of the minimal required frequency. As that boost number is not accurate (and cannot be without a crystal ball), we only use it in a way that allows direct control over the power it is going to cost. This allows keeping a platform-independent level of control over the average power, while allowing for frequency bursts when we know a (set of) tasks can make use of it. In shared policies, the maximum of all CPU's boost is used. Since the extra power expenditure is bounded, it cannot skyrocket even on platforms with a large number of cores in the same frequency domain and/or very high ratio between lowest and highest OPP cost. Signed-off-by: Douglas RAILLARD --- kernel/sched/cpufreq_schedutil.c | 24 +++++++++++++++++------- 1 file changed, 17 insertions(+), 7 deletions(-) diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index 25a410a1ff6a..9a7617ea7bf4 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -228,6 +228,9 @@ static unsigned long sugov_cpu_ramp_boost_update(struct sugov_cpu *sg_cpu) * @sg_policy: schedutil policy object to compute the new frequency for. * @util: Current CPU utilization. * @max: CPU capacity. + * @boost: Extra power that can be spent on top of the minimum amount of power + * required to meet capacity requirements, as a percentage between 0 and + * EM_COST_MARGIN_SCALE. * * If the utilization is frequency-invariant, choose the new frequency to be * proportional to it, that is @@ -246,7 +249,8 @@ static unsigned long sugov_cpu_ramp_boost_update(struct sugov_cpu *sg_cpu) * cpufreq driver limitations. */ static unsigned int get_next_freq(struct sugov_policy *sg_policy, - unsigned long util, unsigned long max) + unsigned long util, unsigned long max, + unsigned long boost) { struct cpufreq_policy *policy = sg_policy->policy; unsigned int freq = arch_scale_freq_invariant() ? @@ -259,7 +263,7 @@ static unsigned int get_next_freq(struct sugov_policy *sg_policy, * Try to get a higher frequency if one is available, given the extra * power we are ready to spend. */ - freq = em_pd_get_higher_freq(pd, freq, 0); + freq = em_pd_get_higher_freq(pd, freq, boost); if (freq == sg_policy->cached_raw_freq && !sg_policy->need_freq_update) return sg_policy->next_freq; @@ -541,6 +545,7 @@ static void sugov_update_single(struct update_util_data *hook, u64 time, unsigned long util, max; unsigned int next_f; bool busy; + unsigned long ramp_boost = 0; sugov_iowait_boost(sg_cpu, time, flags); sg_cpu->last_update = time; @@ -554,10 +559,10 @@ static void sugov_update_single(struct update_util_data *hook, u64 time, busy = !sg_policy->need_freq_update && sugov_cpu_is_busy(sg_cpu); util = sugov_get_util(sg_cpu); - sugov_cpu_ramp_boost_update(sg_cpu); + ramp_boost = sugov_cpu_ramp_boost_update(sg_cpu); max = sg_cpu->max; util = sugov_iowait_apply(sg_cpu, time, util, max); - next_f = get_next_freq(sg_policy, util, max); + next_f = get_next_freq(sg_policy, util, max, ramp_boost); /* * Do not reduce the frequency if the CPU has not been idle * recently, as the reduction is likely to be premature then. @@ -589,14 +594,19 @@ static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time) struct cpufreq_policy *policy = sg_policy->policy; unsigned long util = 0, max = 1; unsigned int j; + unsigned long ramp_boost = 0; for_each_cpu(j, policy->cpus) { struct sugov_cpu *j_sg_cpu = &per_cpu(sugov_cpu, j); - unsigned long j_util, j_max; + unsigned long j_util, j_max, j_ramp_boost; j_util = sugov_get_util(j_sg_cpu); if (j_sg_cpu == sg_cpu) - sugov_cpu_ramp_boost_update(sg_cpu); + j_ramp_boost = sugov_cpu_ramp_boost_update(sg_cpu); + else + j_ramp_boost = sugov_cpu_ramp_boost(j_sg_cpu); + ramp_boost = max(ramp_boost, j_ramp_boost); + j_max = j_sg_cpu->max; j_util = sugov_iowait_apply(j_sg_cpu, time, j_util, j_max); @@ -606,7 +616,7 @@ static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time) } } - return get_next_freq(sg_policy, util, max); + return get_next_freq(sg_policy, util, max, ramp_boost); } static void