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=-11.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 98657C433E7 for ; Wed, 2 Sep 2020 15:48:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 73D1F208B3 for ; Wed, 2 Sep 2020 15:48:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728378AbgIBPso (ORCPT ); Wed, 2 Sep 2020 11:48:44 -0400 Received: from foss.arm.com ([217.140.110.172]:38028 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726310AbgIBN2y (ORCPT ); Wed, 2 Sep 2020 09:28:54 -0400 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 B637711B3; Wed, 2 Sep 2020 06:28:43 -0700 (PDT) Received: from bogus (unknown [10.57.4.218]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B95723F68F; Wed, 2 Sep 2020 06:28:41 -0700 (PDT) Date: Wed, 2 Sep 2020 14:28:38 +0100 From: Sudeep Holla To: Ionela Voinescu Cc: rjw@rjwysocki.net, viresh.kumar@linaro.org, dietmar.eggemann@arm.com, catalin.marinas@arm.com, will@kernel.org, valentin.schneider@arm.com, linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 3/5] cpufreq: report whether cpufreq supports Frequency Invariance (FI) Message-ID: <20200902132838.GF25462@bogus> References: <20200901205549.30096-1-ionela.voinescu@arm.com> <20200901205549.30096-4-ionela.voinescu@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200901205549.30096-4-ionela.voinescu@arm.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 01, 2020 at 09:55:47PM +0100, Ionela Voinescu wrote: > Now that the update of the FI scale factor is done in cpufreq core for > selected functions - target(), target_index() and fast_switch(), > we can provide feedback to the task scheduler and architecture code > on whether cpufreq supports FI. > > For this purpose provide an external function to expose whether the > cpufreq drivers support FI, by using a static key. > > The logic behind the enablement of cpufreq-based invariance is as > follows: > - cpufreq-based invariance is disabled by default > - cpufreq-based invariance is enabled if any of the callbacks > above is implemented while the unsupported setpolicy() is not > > The cpufreq_supports_freq_invariance() function only returns whether > cpufreq is instrumented with the arch_set_freq_scale() calls that > result in support for frequency invariance. Due to the lack of knowledge > on whether the implementation of arch_set_freq_scale() actually results > in the setting of a scale factor based on cpufreq information, it is up > to the architecture code to ensure the setting and provision of the > scale factor to the scheduler. > > Signed-off-by: Ionela Voinescu > Acked-by: Viresh Kumar > Cc: Rafael J. Wysocki > Cc: Viresh Kumar > --- > drivers/cpufreq/cpufreq.c | 16 ++++++++++++++++ > include/linux/cpufreq.h | 5 +++++ > 2 files changed, 21 insertions(+) > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > index 4d5fe777184a..570bf2ebe9d4 100644 > --- a/drivers/cpufreq/cpufreq.c > +++ b/drivers/cpufreq/cpufreq.c > @@ -61,6 +61,12 @@ static struct cpufreq_driver *cpufreq_driver; > static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data); > static DEFINE_RWLOCK(cpufreq_driver_lock); > > +static DEFINE_STATIC_KEY_FALSE(cpufreq_freq_invariance); > +bool cpufreq_supports_freq_invariance(void) > +{ > + return static_branch_likely(&cpufreq_freq_invariance); > +} > + > /* Flag to suspend/resume CPUFreq governors */ > static bool cpufreq_suspended; > > @@ -2720,6 +2726,15 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data) > cpufreq_driver = driver_data; > write_unlock_irqrestore(&cpufreq_driver_lock, flags); > > + /* > + * Mark support for the scheduler's frequency invariance engine for > + * drivers that implement target(), target_index() or fast_switch(). > + */ > + if (!cpufreq_driver->setpolicy) { > + static_branch_enable_cpuslocked(&cpufreq_freq_invariance); > + pr_debug("supports frequency invariance"); > + } > + > if (driver_data->setpolicy) [super nit] while I understand cpufreq_driver = driver_data, it looks odd if 2 consecutive statements refer it with different variables. Or am I confusing myself hugely. -- Regards, Sudeep 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=-11.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 D0B3CC433E2 for ; Wed, 2 Sep 2020 13:30:34 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 916CF20709 for ; Wed, 2 Sep 2020 13:30:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="Az60P9NK" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 916CF20709 Authentication-Results: mail.kernel.org; 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Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kDSog-00011y-B3; Wed, 02 Sep 2020 13:28:46 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kDSoe-00011P-Fh for linux-arm-kernel@lists.infradead.org; Wed, 02 Sep 2020 13:28:45 +0000 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 B637711B3; Wed, 2 Sep 2020 06:28:43 -0700 (PDT) Received: from bogus (unknown [10.57.4.218]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B95723F68F; Wed, 2 Sep 2020 06:28:41 -0700 (PDT) Date: Wed, 2 Sep 2020 14:28:38 +0100 From: Sudeep Holla To: Ionela Voinescu Subject: Re: [PATCH v5 3/5] cpufreq: report whether cpufreq supports Frequency Invariance (FI) Message-ID: <20200902132838.GF25462@bogus> References: <20200901205549.30096-1-ionela.voinescu@arm.com> <20200901205549.30096-4-ionela.voinescu@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200901205549.30096-4-ionela.voinescu@arm.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200902_092844_621757_352921CC X-CRM114-Status: GOOD ( 24.88 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-pm@vger.kernel.org, viresh.kumar@linaro.org, rjw@rjwysocki.net, linux-kernel@vger.kernel.org, dietmar.eggemann@arm.com, catalin.marinas@arm.com, will@kernel.org, valentin.schneider@arm.com, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Sep 01, 2020 at 09:55:47PM +0100, Ionela Voinescu wrote: > Now that the update of the FI scale factor is done in cpufreq core for > selected functions - target(), target_index() and fast_switch(), > we can provide feedback to the task scheduler and architecture code > on whether cpufreq supports FI. > > For this purpose provide an external function to expose whether the > cpufreq drivers support FI, by using a static key. > > The logic behind the enablement of cpufreq-based invariance is as > follows: > - cpufreq-based invariance is disabled by default > - cpufreq-based invariance is enabled if any of the callbacks > above is implemented while the unsupported setpolicy() is not > > The cpufreq_supports_freq_invariance() function only returns whether > cpufreq is instrumented with the arch_set_freq_scale() calls that > result in support for frequency invariance. Due to the lack of knowledge > on whether the implementation of arch_set_freq_scale() actually results > in the setting of a scale factor based on cpufreq information, it is up > to the architecture code to ensure the setting and provision of the > scale factor to the scheduler. > > Signed-off-by: Ionela Voinescu > Acked-by: Viresh Kumar > Cc: Rafael J. Wysocki > Cc: Viresh Kumar > --- > drivers/cpufreq/cpufreq.c | 16 ++++++++++++++++ > include/linux/cpufreq.h | 5 +++++ > 2 files changed, 21 insertions(+) > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > index 4d5fe777184a..570bf2ebe9d4 100644 > --- a/drivers/cpufreq/cpufreq.c > +++ b/drivers/cpufreq/cpufreq.c > @@ -61,6 +61,12 @@ static struct cpufreq_driver *cpufreq_driver; > static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data); > static DEFINE_RWLOCK(cpufreq_driver_lock); > > +static DEFINE_STATIC_KEY_FALSE(cpufreq_freq_invariance); > +bool cpufreq_supports_freq_invariance(void) > +{ > + return static_branch_likely(&cpufreq_freq_invariance); > +} > + > /* Flag to suspend/resume CPUFreq governors */ > static bool cpufreq_suspended; > > @@ -2720,6 +2726,15 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data) > cpufreq_driver = driver_data; > write_unlock_irqrestore(&cpufreq_driver_lock, flags); > > + /* > + * Mark support for the scheduler's frequency invariance engine for > + * drivers that implement target(), target_index() or fast_switch(). > + */ > + if (!cpufreq_driver->setpolicy) { > + static_branch_enable_cpuslocked(&cpufreq_freq_invariance); > + pr_debug("supports frequency invariance"); > + } > + > if (driver_data->setpolicy) [super nit] while I understand cpufreq_driver = driver_data, it looks odd if 2 consecutive statements refer it with different variables. Or am I confusing myself hugely. -- Regards, Sudeep _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel