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[209.132.180.67]) by mx.google.com with ESMTP id a19-v6si14031192pgv.47.2018.06.19.02.49.24; Tue, 19 Jun 2018 02:49:38 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757129AbeFSJrW (ORCPT + 99 others); Tue, 19 Jun 2018 05:47:22 -0400 Received: from mail-wr0-f196.google.com ([209.85.128.196]:41390 "EHLO mail-wr0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757105AbeFSJrT (ORCPT ); Tue, 19 Jun 2018 05:47:19 -0400 Received: by mail-wr0-f196.google.com with SMTP id h10-v6so19827791wrq.8 for ; Tue, 19 Jun 2018 02:47:18 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=jOqdzx8JvKt04nMMfEEg7WjmjaALe+bxCwuJYwj1Mko=; b=Ug2bnlYsvKgThDbYls7JiIaObSPhE3OFQJHlxX4EHChAQOG1vCAzcCsQtutVhshktl VBI+BYUrzGw5cMTqCSOl+CplWWYQ5ZJ7tvAeiYhjDSReWoIp/Ety9b6QZ4Yx8sDyDR+U WezJg0BhZpPEwVZzgDA0r1npjYO7jsZZ5MlvZ9AT9UGpi05jaGPRo+gfjfL3c0tikWur auWgd69vkRjxzDioWUPkXpiYg10R/UQdRqXhyh/IHLWB+Eu89Yld53cQmH/3zQgMiAl4 RIWBzqOTO1yc7ofs0RqwrMM05KyvNB87u06qPVBaBpYh7FqAf72XdrbeFruXIJU4YXjs chrQ== X-Gm-Message-State: APt69E3EAhRJ9gAutbJYGijsMC7Y5qhBarjJmoJEK3vpXfTakCQfhwvi b7v2o/wZLUFsbqQp3MgRo80AEA== X-Received: by 2002:adf:9dc9:: with SMTP id q9-v6mr13944993wre.12.1529401637946; Tue, 19 Jun 2018 02:47:17 -0700 (PDT) Received: from localhost.localdomain ([151.15.207.242]) by smtp.gmail.com with ESMTPSA id n17-v6sm16650203wrs.96.2018.06.19.02.47.16 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 19 Jun 2018 02:47:17 -0700 (PDT) Date: Tue, 19 Jun 2018 11:47:14 +0200 From: Juri Lelli To: Quentin Perret Cc: Pavan Kondeti , peterz@infradead.org, rjw@rjwysocki.net, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, mingo@redhat.com, dietmar.eggemann@arm.com, morten.rasmussen@arm.com, chris.redpath@arm.com, patrick.bellasi@arm.com, valentin.schneider@arm.com, vincent.guittot@linaro.org, thara.gopinath@linaro.org, viresh.kumar@linaro.org, tkjos@google.com, joelaf@google.com, smuckle@google.com, adharmap@quicinc.com, skannan@quicinc.com, edubezval@gmail.com, srinivas.pandruvada@linux.intel.com, currojerez@riseup.net, javi.merino@kernel.org Subject: Re: [RFC PATCH v3 10/10] arch_topology: Start Energy Aware Scheduling Message-ID: <20180619094714.GA13617@localhost.localdomain> References: <20180521142505.6522-1-quentin.perret@arm.com> <20180521142505.6522-11-quentin.perret@arm.com> <20180619091841.GD9208@codeaurora.org> <20180619094002.GR17720@e108498-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180619094002.GR17720@e108498-lin.cambridge.arm.com> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 19/06/18 10:40, Quentin Perret wrote: > Hi Pavan, > > On Tuesday 19 Jun 2018 at 14:48:41 (+0530), Pavan Kondeti wrote: [...] > > There seems to be a sysfs interface exposed by this driver to change cpu_scale. > > Should we worry about it? I don't know what is the usecase for changing the > > cpu_scale from user space. > > This is something I've been wondering as well. TBH, I'm not sure what to > do in this case. And I'm not sure to know what is the use-case either. > Debugging purpose I assume ? > > Juri, did you have a specific use-case for this feature when the > arch_topology driver was first introduced ? Or was it just to align > with the existing arm/arm64 code ? It was requested (IIRC) because DT might have bogus values and not be easily modifiable. So, this is another way to get things right for your platform at runtime.