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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4FC2BC433F5 for ; Mon, 4 Apr 2022 16:02:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=XvixsKGUpeygNAKfgbD7j5/04VER2C/pBMOFMPywhlQ=; b=iedAm+YoqCjboc FCsXey0xf4ss4SGCvvbvt4MmZCPkXkgJMjItuY7DlfLF7NVRUAxdDmAADGOMvzT6vizbfjSecy9cu 0s2CCLizYP8eyDMm5COS+MDpu1yYre+yGCy2hu1vm1bBJAD4KT2TighEFZkYF1be1+jKKD4Nt/SfZ D313akz2P7L4/K9ZGbVw1tBEUJl0k1p6qbM61tryzG/8ce8ZKlybdH8Ndqw/W0sV8IA+m/h2SIhLN /q9ER/jHhnpTTJX6t52CazYTMAjh9+cJHvgjNGEtGQ0DL3udMhO+nJzMGsWafzQ9myNwXWxAImJ8t Vydtdo3BHYU7Pe0wXqgQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nbP8U-00FfWe-OC; Mon, 04 Apr 2022 16:00:58 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nbP8R-00FfSx-49; Mon, 04 Apr 2022 16:00:56 +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 E3756D6E; Mon, 4 Apr 2022 09:00:49 -0700 (PDT) Received: from localhost (ionvoi01-desktop.cambridge.arm.com [10.1.196.65]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 888053F73B; Mon, 4 Apr 2022 09:00:49 -0700 (PDT) Date: Mon, 4 Apr 2022 17:00:47 +0100 From: Ionela Voinescu To: Lukasz Luba Cc: linux-kernel@vger.kernel.org, dietmar.eggemann@arm.com, Pierre.Gondois@arm.com, viresh.kumar@linaro.org, rafael@kernel.org, daniel.lezcano@linaro.org, linux-pm@vger.kernel.org, mka@chromium.org, nm@ti.com, sboyd@kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, cristian.marussi@arm.com, sudeep.holla@arm.com, matthias.bgg@gmail.com Subject: Re: [RESEND][PATCH 1/8] PM: EM: Add .get_cost() callback Message-ID: References: <20220321095729.20655-1-lukasz.luba@arm.com> <20220321095729.20655-2-lukasz.luba@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220321095729.20655-2-lukasz.luba@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220404_090055_317528_E9ED3D4E X-CRM114-Status: GOOD ( 28.18 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 Monday 21 Mar 2022 at 09:57:22 (+0000), Lukasz Luba wrote: > The Energy Model (EM) supports devices which report abstract power scale, > not only real Watts. The primary goal for EM is to enable the Energy Aware > Scheduler (EAS) for a given platform. Some of the platforms might not be > able to deliver proper power values. The only information that they might > have is the relative efficiency between CPU types. > > Thus, it makes sense to remove some restrictions in the EM framework and > introduce a mechanism which would support those platforms. What is crucial > for EAS to operate is the 'cost' field in the EM. The 'cost' is calculated > internally in EM framework based on knowledge from 'power' values. > The 'cost' values must be strictly increasing. The existing API with its > 'power' value size restrictions cannot guarantee that the 'cost' will meet > this requirement. > > Since the platform is missing this detailed information, but has only > efficiency details, introduce a new custom callback in the EM framework. > The new callback would allow to provide the 'cost' values which reflect > efficiency of the CPUs. This would allow to provide EAS information which > has different relation than what would be forced by the EM internal > formulas calculating 'cost' values. Thanks to this new callback it is > possible to create a system view for EAS which has no overlapping > performance states across many Performance Domains. > > Signed-off-by: Lukasz Luba > --- > include/linux/energy_model.h | 24 +++++++++++++++++++++++- > 1 file changed, 23 insertions(+), 1 deletion(-) > > diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h > index 9f3c400bc52d..0a3a5663177b 100644 > --- a/include/linux/energy_model.h > +++ b/include/linux/energy_model.h > @@ -114,9 +114,30 @@ struct em_data_callback { > */ > int (*active_power)(unsigned long *power, unsigned long *freq, > struct device *dev); > + > + /** > + * get_cost() - Provide the cost at the given performance state of > + * a device > + * @dev : Device for which we do this operation (can be a CPU) > + * @freq : Frequency at the performance state in kHz > + * @cost : The cost value for the performance state > + * (modified) > + * > + * In case of CPUs, the cost is the one of a single CPU in the domain. > + * It is expected to fit in the [0, EM_MAX_POWER] range due to internal > + * usage in EAS calculation. > + * > + * Return 0 on success, or appropriate error value in case of failure. > + */ > + int (*get_cost)(struct device *dev, unsigned long freq, > + unsigned long *cost); > }; > -#define EM_DATA_CB(_active_power_cb) { .active_power = &_active_power_cb } > #define EM_SET_ACTIVE_POWER_CB(em_cb, cb) ((em_cb).active_power = cb) > +#define EM_ADV_DATA_CB(_active_power_cb, _cost_cb) \ > + { .active_power = _active_power_cb, \ > + .get_cost = _cost_cb } > +#define EM_DATA_CB(_active_power_cb) \ > + EM_ADV_DATA_CB(_active_power_cb, NULL) > > struct em_perf_domain *em_cpu_get(int cpu); > struct em_perf_domain *em_pd_get(struct device *dev); > @@ -264,6 +285,7 @@ static inline int em_pd_nr_perf_states(struct em_perf_domain *pd) > > #else > struct em_data_callback {}; > +#define EM_ADV_DATA_CB(_active_power_cb, _cost_cb) { } > #define EM_DATA_CB(_active_power_cb) { } > #define EM_SET_ACTIVE_POWER_CB(em_cb, cb) do { } while (0) > Reviewed-by: Ionela Voinescu Thanks, Ionela. > -- > 2.17.1 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel