From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0D386C5DF61 for ; Thu, 7 Nov 2019 10:49:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C48BB21882 for ; Thu, 7 Nov 2019 10:49:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="VrPFocA9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387924AbfKGKtH (ORCPT ); Thu, 7 Nov 2019 05:49:07 -0500 Received: from mail-wr1-f67.google.com ([209.85.221.67]:44456 "EHLO mail-wr1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727707AbfKGKtG (ORCPT ); Thu, 7 Nov 2019 05:49:06 -0500 Received: by mail-wr1-f67.google.com with SMTP id f2so2405656wrs.11 for ; Thu, 07 Nov 2019 02:49:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to :user-agent; bh=BoJC2vTkuWcgoU9/Gd+NZ3si/SA7xiwzAE9kV4SdCkQ=; b=VrPFocA9qBjuCcuN8Tn5qHHG8bdYdAAfDQXKn7yQF4JsYcVDKDKg8LZbIrc8M0c+UR Uu46B6aPG+9GSNvUn3rMsVn98X/y2ci3T4qtdUCWyXITGWU30nzdKYcHCM4MhXYIJpTA qWK24YuKpxU/ho6LtVdkjQnORnE0nmyfo64+sW7JYOOSKE6JwJzKGLbIzx2sXnkGtGuw qMDxMdIL9aFAleVNvsXKquPC1SPET6RMeZuZEaM3ETeoVxXgLggxgCFz7kBPpvVGNywI 5mWEoD9kS6DDnOuZlZSuNDWyj/7mE03GpthdFKL3qPt5fafJ8+LUmVmP0c3cd2+yMK29 LDwQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to:user-agent; bh=BoJC2vTkuWcgoU9/Gd+NZ3si/SA7xiwzAE9kV4SdCkQ=; b=DhKwA6I0KfIjlwy1Nty3g8+oxQv1Z8JzJg0KnPqDk6QjUlgwiON5vb1JSmg/XxSbJI WJlS7A0uEh3QbZ7iSdyxgS4LCrIPTJH8dOA2MiJ2rbrKdQTD6i4eTvhkcBqCJwXNY6ww XI/I54ZaOsDzRRp2C2ONYv7mfv6P8l3mKphDMyWggKDkyaNrLHdRXxXbNnx78YgH8fZ+ 9CPtpf9Obq9a+jKrvm05Q2777jKNSM54m+AmM2XMFlLqLrkRDCzM6ACyYRi7CrkEtmeP bFM3/JAa7nslkidZ7GATUddYm9BP9Isbpp6fbkwYaPrj/8TRtQ+y0aEX1yICLN03w8hJ 5VIg== X-Gm-Message-State: APjAAAWYuJmbhdwp2BkZKC82sUpE50z+ZkiwFw5CSBX4lamfZkyW+0Uu kEjaPd+W4+wjp+XwYBJoUlbGlA== X-Google-Smtp-Source: APXvYqzOETIKdw2q2EWHS49YE7Q9FgbNjhavNXZvbJwd9forsxCnZjVAbHexquaz+zezZ4hQZP0eBQ== X-Received: by 2002:a5d:4f06:: with SMTP id c6mr2186806wru.211.1573123744329; Thu, 07 Nov 2019 02:49:04 -0800 (PST) Received: from linaro.org ([2a01:e0a:f:6020:7de6:e8c6:ca61:22f0]) by smtp.gmail.com with ESMTPSA id w81sm2074459wmg.5.2019.11.07.02.49.02 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 07 Nov 2019 02:49:03 -0800 (PST) Date: Thu, 7 Nov 2019 11:49:01 +0100 From: Vincent Guittot To: Thara Gopinath Cc: mingo@redhat.com, peterz@infradead.org, ionela.voinescu@arm.com, rui.zhang@intel.com, edubezval@gmail.com, qperret@google.com, linux-kernel@vger.kernel.org, amit.kachhap@gmail.com, javi.merino@kernel.org, daniel.lezcano@linaro.org Subject: Re: [Patch v5 6/6] sched/fair: Enable tuning of decay period Message-ID: <20191107104901.GA472@linaro.org> References: <1572979786-20361-1-git-send-email-thara.gopinath@linaro.org> <1572979786-20361-7-git-send-email-thara.gopinath@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1572979786-20361-7-git-send-email-thara.gopinath@linaro.org> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le Tuesday 05 Nov 2019 à 13:49:46 (-0500), Thara Gopinath a écrit : > Thermal pressure follows pelt signas which means the > decay period for thermal pressure is the default pelt > decay period. Depending on soc charecteristics and thermal > activity, it might be beneficial to decay thermal pressure > slower, but still in-tune with the pelt signals. > One way to achieve this is to provide a command line parameter > to set a decay shift parameter to an integer between 0 and 10. > > Signed-off-by: Thara Gopinath > --- > > v4->v5: > - Changed _coeff to _shift as per review comments on the list. > > Documentation/admin-guide/kernel-parameters.txt | 5 +++++ > kernel/sched/fair.c | 25 +++++++++++++++++++++++-- > 2 files changed, 28 insertions(+), 2 deletions(-) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index c82f87c..0b8f55e 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -4281,6 +4281,11 @@ > incurs a small amount of overhead in the scheduler > but is useful for debugging and performance tuning. > > + sched_thermal_decay_shift= > + [KNL, SMP] Set decay shift for thermal pressure signal. > + Format: integer betweer 0 and 10 > + Default is 0. > + > skew_tick= [KNL] Offset the periodic timer tick per cpu to mitigate > xtime_lock contention on larger systems, and/or RCU lock > contention on all systems with CONFIG_MAXSMP set. > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 5f6c371..61a020b 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -91,6 +91,18 @@ const_debug unsigned int sysctl_sched_migration_cost = 500000UL; > * and maximum available capacity due to thermal events. > */ > static DEFINE_PER_CPU(unsigned long, thermal_pressure); > +/** > + * By default the decay is the default pelt decay period. > + * The decay shift can change the decay period in > + * multiples of 32. > + * Decay shift Decay period(ms) > + * 0 32 > + * 1 64 > + * 2 128 > + * 3 256 > + * 4 512 > + */ > +static int sched_thermal_decay_shift; > > static void trigger_thermal_pressure_average(struct rq *rq); > > @@ -10435,6 +10447,15 @@ void update_thermal_pressure(int cpu, unsigned long capped_capacity) > delta = arch_scale_cpu_capacity(cpu) - capped_capacity; > per_cpu(thermal_pressure, cpu) = delta; > } > + > +static int __init setup_sched_thermal_decay_shift(char *str) > +{ > + if (kstrtoint(str, 0, &sched_thermal_decay_shift)) > + pr_warn("Unable to set scheduler thermal pressure decay shift parameter\n"); > + > + return 1; > +} > +__setup("sched_thermal_decay_shift=", setup_sched_thermal_decay_shift); > #endif > > /** > @@ -10444,8 +10465,8 @@ void update_thermal_pressure(int cpu, unsigned long capped_capacity) > static void trigger_thermal_pressure_average(struct rq *rq) > { > #ifdef CONFIG_SMP > - update_thermal_load_avg(rq_clock_task(rq), rq, > - per_cpu(thermal_pressure, cpu_of(rq))); > + update_thermal_load_avg(rq_clock_task(rq) >> sched_thermal_decay_shift, > + rq, per_cpu(thermal_pressure, cpu_of(rq))); Would be better to create +static inline u64 rq_clock_thermal(struct rq *rq) +{ + lockdep_assert_held(&rq->lock); + assert_clock_updated(rq); + + return rq_clock_task(rq) >> sched_thermal_decay_shift; +} + and use it when calling update_thermal_load_avg(rq_clock_thermal(rq)... > #endif > } > > -- > 2.1.4 >