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 2E801161314 for ; Thu, 11 Jul 2024 13:59:53 +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=1720706395; cv=none; b=YcokNRn9XRXqo3t16pabD5rxcLob6pQYOP0d939HywldiN08++ZgO0EpipmZU6HLVFVqhYWQdx6k/dsfxSp4B6iANMdr4FGWpouF0GpoE84fTLUWtXS0JvFXWpvBB+kmRZntlPMdTMYkYR7vLssjzzSdEFX0t92RHILyG7jFk6E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720706395; c=relaxed/simple; bh=7dV4ckuhGGV0wUAI/+cK+Tifo24B23NojR32tXkLDiA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=YZxLeBkju56OQmBCaGIdoJbbFWLFYjlyDIzoUqrM3qkhPkEoRoZhEdYnCaN1udZDfERr1iOyBgZMAQoTht2s0VQdUvF6JsjZy7lbA59O6GMyHixewtTzpR/Y8U0sKkNHZr/vjSUKQPVkF7DTOV6+ju7kmCnPUTGZaiVK91Pvx9c= 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 B094DFEC; Thu, 11 Jul 2024 07:00:18 -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 727983F766; Thu, 11 Jul 2024 06:59:50 -0700 (PDT) Date: Thu, 11 Jul 2024 15:59:19 +0200 From: Beata Michalska To: Catalin Marinas Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, ionela.voinescu@arm.com, sudeep.holla@arm.com, will@kernel.org, vincent.guittot@linaro.org, vanshikonda@os.amperecomputing.com, sumitg@nvidia.com, yang@os.amperecomputing.com, lihuisong@huawei.com, viresh.kumar@linaro.org, rafael@kernel.org Subject: Re: [PATCH v6 0/4] Add support for AArch64 AMUv1-based arch_freq_get_on_cpu Message-ID: References: <20240603082154.3830591-1-beata.michalska@arm.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: Hi Catalin, On Mon, Jul 08, 2024 at 06:10:02PM +0100, Catalin Marinas wrote: > Hi Beata, > > On Mon, Jun 03, 2024 at 09:21:50AM +0100, 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. Note that some small discrepancies have been observed while > > testing (on the model) and this is currently being investigated, though it > > should not have any significant impact on the overall results. > > What's the plan with this series? Are you still investigating those > discrepancies or is it good to go? > Overall it should be good to go with small caveat: as per discussion [1] we might need to provide new sysfs attribute exposing an average frequency instead of plugging new code under existing cpuinfo_cur_freq. This is to avoid messing up with other archs and make a clean distinction on which attribute provides what information. As such, the arch_freq_get_on_cpu implementation provided within this series [PATCH v6 3/4] will most probably be shifted to a new function. Hopefully will be able to send those changes soon. --- [1] https://lore.kernel.org/all/ZmrB_DqtmVpvG30l@arm.com/ --- BR Beata > -- > Catalin