From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from fanzine2.igalia.com (fanzine2.igalia.com [213.97.179.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 81260268691; Thu, 22 May 2025 08:36:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.97.179.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747902974; cv=none; b=ta30B5cUryBVho5SCau/CTk4y7LXADlPz2SeuqPdRCWpP2bU32QDqSz8d+uKgf54Sp3SA8RVGBVDma+LOGwLTvm/HX0yDA3BISm3EMlv47vVo6XFvYFDsWhU+2OcI4Sk3rmO+9/bae1sVUverElGNFdgiTCt48FdSzePBgaskFs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747902974; c=relaxed/simple; bh=0iqH3SFau2Ad0MLJhsn1yGSNEsRQWQL4MBklLj1xHpc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ANQ/rz3QZJKjhTpYlayI4SV15B2Ll4TDt9tP+xgA91NMBAvVJ7HrG0K9/YelyHe6/6/8TJabGfcGG+vv07u8kJSJBfV7mVnfstNaEqTs2vhJray6jck/bdxM9inDGcKCVGX0U/R4bB4fZd3XbZiFyF0GLjR31PmiEdihbBtN3oU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=igalia.com; spf=pass smtp.mailfrom=igalia.com; dkim=pass (2048-bit key) header.d=igalia.com header.i=@igalia.com header.b=aw1ic9y4; arc=none smtp.client-ip=213.97.179.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=igalia.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=igalia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=igalia.com header.i=@igalia.com header.b="aw1ic9y4" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:From: References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=MlBjh67fGAfaX5KmbbcZM9E/1HTJY8YOYuHSiHb/X8g=; b=aw1ic9y4PyfVRDebLTLqFx8AOM j1uaR058N/V3dYnT6vvo65fUpuBqhwjqZBTmBAmf34hT6QrL36k1du5c3CGxF3dj2GirdrctCjJhO 4oU8xknCmvl1ZBkc9ZtcfFY4XlGTCwkYMydJNh3sEX7jyfFaUWH/ndkMItPWeLlsI6nsISmLUgPdo QPLnN/b8yMAPM09zUOkCAUXFZZtawKC1EHJqJSHfkoXydgqYxHP0lpBAY1wEplne9yIPhyMzNVpb8 brpOjWA1Jjx2G5NzsOaEb5t89ihzHZ2SaKK8QahCiYgkpQAyxnI0cFfOiWdQDrJfbevIStQ5rCJSj 3B/hdWnw==; Received: from [106.101.7.122] (helo=[192.168.210.21]) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_128_GCM:128) (Exim) id 1uI1PH-00Bcfi-Ew; Thu, 22 May 2025 10:36:03 +0200 Message-ID: Date: Thu, 22 May 2025 17:35:55 +0900 Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] PM: EM: Add inotify support when the energy model is updated. To: Lukasz Luba Cc: christian.loehle@arm.com, tj@kernel.org, pavel@kernel.org, kernel-dev@igalia.com, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, len.brown@intel.com, "Rafael J. Wysocki" References: <20250507014728.6094-1-changwoo@igalia.com> <90834b07-9261-4be6-a10b-88d3f5308e1e@igalia.com> <96b4ae67-b9a8-47d3-a951-a880848e6719@arm.com> From: Changwoo Min Content-Language: en-US, ko-KR, en-US-large, ko In-Reply-To: <96b4ae67-b9a8-47d3-a951-a880848e6719@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 5/22/25 17:19, Lukasz Luba wrote: > > > On 5/10/25 12:34, Rafael J. Wysocki wrote: >> On Sat, May 10, 2025 at 7:07 AM Changwoo Min wrote: >>> I am curious about whether the energy mode is likely to be updated more >>> often with this change. How often the energy model is likely to be >>> updated is the factor to be considered for the interface and the model >>> to post-processing the eneergy model (in the BPF schedulers). >> >> It really is hard to say precisely because eventually this will depend >> on the platform firmware.  Hopefully, this is not going to happen too >> often, but if the thermal envelope of the platform is tight, for >> instance, it may not be the case. > > It's hard to say for all use cases, but there are some easy to measure > and understand: > > 1. Long scenarios with heavy GPU usage (e.g. gaming). Power on CPUs >    built from High-Performance cells can be affected by +20% and after >    ~1min > 2. Longer recording with heavy ISP usage, similar to above > > In those two, it's sufficient to update the EM every 1-3sec to reach > this +20% after 60sec. Although, at the beginning when the GPU starts > heating the updates should happen a bit more often. > > There are some more complex cases, e.g. when more than 1 Big CPU does > heavy computations and the heat is higher than normal EM model of > single CPU (even for that scenario profile). Then the updates to EM > can go a bit more often (it depends what the platform would like > to leverage and achieve w/ SW). Thank you for the further clarification. I think the netlink notification should be fast and efficient enough to cover these scenarios. Regards, Changwoo Min