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 B50E25336D for ; Wed, 13 Mar 2024 23:50:38 +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=1710373840; cv=none; b=GG/qTN82VW+Vsn7XwQFRtiJKy4+U55tJ1N5qrdGa7naekFkB21C7ZGgnVJYCMwJtUlBEB26hO8ByvbBgweqFfWUg8gnKiA+2HwaNJwxGeOJ/LYufvdN2+aZ2c/pv7/mUdmMGf0YXXjS0eTWQDxlHbH63elphNbJgztOz8S2X2jc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710373840; c=relaxed/simple; bh=ByyhjiMnk2+hZUiI7OFtRvQm1bF5Rd89kOoggsgFmp8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=YaibxuKc509wJiqng5A5CnuJfgZe93UzSZf1YswVKoCv1X/QG4803jOtdCdR7Aa0stscHbv0YIdJ19yl8paMxrhKmbk388yvZsCkJbOwgDsqveYEHRG718P2CNgL04tmRih3njH4t+ON5FPnkz9TLkHeAnRRLmTvEbcR2YsnClQ= 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 A142C1007; Wed, 13 Mar 2024 16:51:14 -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 5ACF03F73F; Wed, 13 Mar 2024 16:50:34 -0700 (PDT) Date: Thu, 14 Mar 2024 00:49:57 +0100 From: Beata Michalska To: Ionela Voinescu Cc: 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, sumitg@nvidia.com, yang@os.amperecomputing.com, lihuisong@huawei.com 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> 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: On Wed, Mar 13, 2024 at 12:27:53PM +0000, Ionela Voinescu wrote: > Hey, > > 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. > > > > arch/arm64/kernel/topology.c | 116 +++++++++++++++++++++++++++++++---- > > drivers/base/arch_topology.c | 8 ++- > > 2 files changed, 110 insertions(+), 14 deletions(-) > > > > -- > > 2.25.1 > >