From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 6775D15667F; Wed, 3 Apr 2024 21:30:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712179839; cv=none; b=Q05BgAlhfmbh8wwZtMuJWe7VJqzEEtFZH5Fju7KWYjm/julLH66VCkYU+E9LayKrYn+KfzbwwGKiKKiFMDX3MFtVpo4NLrKq1oXHhWlVNqFUcFTsKjiu6bFEPkBy6jMf3mDUAlGUwPBe5NNw50eepzmLbcv2p9ixppREAZuaWYE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712179839; c=relaxed/simple; bh=JFTzffzxYgfa4xgo4DxPkjtxEM7+SaShc37kUgIUqRI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=joU8SMG/c5tBvWp1GzzrwuQx+AAM9HpSEr9YNfbBuCBmbWxtda5i3uHWy28TwxA4ywVP05upQppprbUi5NvyzjxXPyHLu5QwvrP1Zu0VIMXilo3Mw+HY49fKHMIGORy83Gr3ZbHpvPI3zx7iOfRz1tNOJOQtvNL3qUrz68ue+cQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com 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 72ABE1007; Wed, 3 Apr 2024 14:31:07 -0700 (PDT) Received: from arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 9ED5D3F7B4; Wed, 3 Apr 2024 14:30:33 -0700 (PDT) Date: Wed, 3 Apr 2024 23:30:33 +0200 From: Beata Michalska To: Sumit Gupta Cc: Ionela Voinescu , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, vanshikonda@os.amperecomputing.com, sudeep.holla@arm.com, will@kernel.org, catalin.marinas@arm.com, vincent.guittot@linaro.org, yang@os.amperecomputing.com, lihuisong@huawei.com, linux-tegra Subject: Re: [PATCH v3 0/3] Add support for AArch64 AMUv1-based arch_freq_get_on_cpu Message-ID: References: <20240312083431.3239989-1-beata.michalska@arm.com> <21a78951-2d4a-1d6e-0cd8-6a4a75ccb142@nvidia.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <21a78951-2d4a-1d6e-0cd8-6a4a75ccb142@nvidia.com> On Wed, Mar 20, 2024 at 10:22:22PM +0530, Sumit Gupta wrote: > Hi Beata, > > > > On Tuesday 12 Mar 2024 at 08:34:28 (+0000), Beata Michalska wrote: > > > > Introducing arm64 specific version of arch_freq_get_on_cpu, cashing on > > > > existing implementation for FIE and AMUv1 support: the frequency scale > > > > factor, updated on each sched tick, serves as a base for retrieving > > > > the frequency for a given CPU, representing an average frequency > > > > reported between the ticks - thus its accuracy is limited. > > > > > > > > The changes have been rather lightly (due to some limitations) tested on > > > > an FVP model. > > > > > > > > Relevant discussions: > > > > [1] https://lore.kernel.org/all/20240229162520.970986-1-vanshikonda@os.amperecomputing.com/ > > > > [2] https://lore.kernel.org/all/7eozim2xnepacnnkzxlbx34hib4otycnbn4dqymfziqou5lw5u@5xzpv3t7sxo3/ > > > > [3] https://lore.kernel.org/all/20231212072617.14756-1-lihuisong@huawei.com/ > > > > [4] https://lore.kernel.org/lkml/ZIHpd6unkOtYVEqP@e120325.cambridge.arm.com/T/#m4e74cb5a0aaa353c60fedc6cfb95ab7a6e381e3c > > > > > > > > v3: > > > > - dropping changes to cpufreq_verify_current_freq > > > > - pulling in changes from Ionela initializing capacity_freq_ref to 0 > > > > (thanks for that!) and applying suggestions made by her during last review: > > > > - switching to arch_scale_freq_capacity and arch_scale_freq_ref when > > > > reversing freq scale factor computation > > > > - swapping shift with multiplication > > > > - adding time limit for considering last scale update as valid > > > > - updating frequency scale factor upon entering idle > > > > > > > > v2: > > > > - Splitting the patches > > > > - Adding comment for full dyntick mode > > > > - Plugging arch_freq_get_on_cpu into cpufreq_verify_current_freq instead > > > > of in show_cpuinfo_cur_freq to allow the framework to stay more in sync > > > > with potential freq changes > > > > > > > > Beata Michalska (2): > > > > arm64: Provide an AMU-based version of arch_freq_get_on_cpu > > > > arm64: Update AMU-based frequency scale factor on entering idle > > > > > > > > Ionela Voinescu (1): > > > > arch_topology: init capacity_freq_ref to 0 > > > > > > > > > > Should there have been a patch that adds a call to > > > arch_freq_get_on_cpu() from show_cpuinfo_cur_freq() as well? > > > > > > My understanding from this [1] thread and others referenced there is > > > that was something we wanted. > > > > > Right, so I must have missunderstood that, as the way I did read it was that > > it is acceptable to keep things as they are wrt cpufreq sysfs entries. > > > > --- > > BR > > Beata > > > [1] https://lore.kernel.org/lkml/2cfbc633-1e94-d741-2337-e1b0cf48b81b@nvidia.com/ > > > > > > Thanks, > > > Ionela. > > > > > Yes, the change to show_cpuinfo_cur_freq from [1] is needed. > Noted. Will send an update including fixes and this requested change. --- BR Beata > [1] > https://lore.kernel.org/lkml/20230606155754.245998-1-beata.michalska@arm.com/ > > Thank you, > Sumit Gupta