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 36968C3DA45 for ; Thu, 11 Jul 2024 14:00:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=76Kf/vr7PoAxpzDqbwA5CparLO2FgxrloUFjHU5OVfA=; b=MF2ib7KXTLmuuBjp9z1ov5hJuC lIHtHMmuV4y9pMQqLGpPMCJZ7mVr9c2EjJ4YJPdhgKycU5cRMVd58kV6CfiNVmuUbp7wxqc540vGH BDacJntFrZnc8DzdH/b47Eso93dNZ8Pbdrg4iyTP72Qfo74AmSzzg1lXG1aB5WANyR2y0V6+/8nHL 8tmBal0Y1GE1Bdgqjh5XE81UTlU8jVv2R/GQAQNgZVI1amkSdJ45Olv0kdCgOLaWs7yL7E4sjSm8S SQrA+/dmrv/6Z7PjiYo7anDINQeRKS4AY5h13VDxCjF1rSxpmAz2qH2RGULeWQYHtW/rzCV0SAs5J 35NqVJQA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sRuLH-0000000EFbX-1b5C; Thu, 11 Jul 2024 14:00:15 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sRuKz-0000000EFWP-2Vw7 for linux-arm-kernel@lists.infradead.org; Thu, 11 Jul 2024 13:59:59 +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 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240711_065957_707438_946506F6 X-CRM114-Status: GOOD ( 18.21 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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