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 159C8383BE for ; Tue, 19 Mar 2024 22:48:50 +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=1710888533; cv=none; b=AitBrGMz/SI1EGbz0ypTIpQ1xKYxT7N/cOdje/dtN7GiiAJ/2uAsKebuhp7azMc+FlwKzxtzldTpF6sg/kd8PUIcIpQUE5SN5t9AcQf6u756Fm7sUgU/MB67995a370HILkYH5qmfqWgq7Gs3T1BVbuDdEq4Qaq7JtSKZuj7hEQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710888533; c=relaxed/simple; bh=kxjEKzdOBmYjrpPcv7qKt9KYCnZ2M4/p1rQW9uyk5T4=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Un0T0uQz+lkJolo42DMQeMRnzv992WwDvIR+UT/0yhOJxmO0kziCvH0bZCySKBLIubotE2WvCLRnHm4AnevekwJjjmhqWv5BZiL9aZXCZh1qkAkGJoHzOoZcRvJrLFZoAx+IsYHcTbLmu/zA3tBmcUrASNqfmNR4LwSv8iEr3QU= 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 096D0DA7; Tue, 19 Mar 2024 15:49:24 -0700 (PDT) Received: from minigeek.lan (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id DC16E3F64C; Tue, 19 Mar 2024 15:48:45 -0700 (PDT) Date: Tue, 19 Mar 2024 22:48:23 +0000 From: Andre Przywara To: Amit Singh Tomar Cc: Yangtao Li , Viresh Kumar , Nishanth Menon , Stephen Boyd , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Chen-Yu Tsai , Jernej Skrabec , Samuel Holland , "Rafael J . Wysocki" , "linux-pm@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-sunxi@lists.linux.dev" , "linux-arm-kernel@lists.infradead.org" , Brandon Cheo Fusi , Martin Botka , Martin Botka Subject: Re: [PATCH v2 8/8] arm64: dts: allwinner: h616: enable DVFS for all boards Message-ID: <20240319224823.69af2ee4@minigeek.lan> In-Reply-To: References: <20240318105153.2c666647@donnerap.manchester.arm.com> <8425a1a2-8453-b705-2c14-a846fa05ae21@marvell.com> <20240318230333.72c1b6ed@minigeek.lan> Organization: Arm Ltd. X-Mailer: Claws Mail 4.2.0 (GTK 3.24.31; x86_64-slackware-linux-gnu) Precedence: bulk X-Mailing-List: linux-sunxi@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Wed, 20 Mar 2024 00:57:22 +0530 Amit Singh Tomar wrote: Hi, > >> Okay, it would be interesting to see results of some benchmark here. > > > > But why? This is not a performance optimisation, it's adding a missing > > feature, because the CPU was locked to 1 GHz before, for safety > > reasons, due to missing thermal and DVFS capability. Now it's able to > > run at up to 1.5 GHz, as specified. > I completely understand, it's not intended for performance optimization. > > > If you are upset about the bold claim, I can just remove it from the > > commit message, it was just a heads up that we were leaving a lot of > > performance on the table at the moment. > I was merely curious about it, not upset. It could certainly enhance > aspects such as memory bandwidth, Of all the things I would expect the memory bandwidth to stay the same, as the clock rate of the memory controller did not change. > but perhaps not to the extent as > suggested. Therefore, rephrasing the commit message should suffice. I can certainly do that, but you probably missed that small little number at the end of my benchmark instructions. That tells you that I indeed measured a 49.8 % performance uplift with the linpack benchmark. And I would expect anything similarly CPU bound to react in the same fashion. Please try it yourself, you don't even need this particular piece of hardware, just some machine with working cpufreq. Cheers, Andre