From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) (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 AA73B3939B2 for ; Tue, 13 Jan 2026 15:39:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.176.79.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768318788; cv=none; b=Cqvy2rvn4JpyKHbZQA4500tsu0BGdSnboEtI2pFC/3bZHeXWvmUfFF2yZCVg9TA7fztH64uFq8hKMgtgLlH0iPtKtXVmcm0DI/YBqT80yyNCoEQ9O3bSwxVRgdJGCvnSGE2UYiM4f60K7G2HBF7cwwcmkee3JuneaQfc2O3oafs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768318788; c=relaxed/simple; bh=Kcdt6ezZS7r5e8cIC6YRtm7HY+hZIKH7R6q1b/F9slE=; h=Date:From:To:CC:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=HaoIH+28MSpZ8K+DC3kKyj18opp96u1k+0DKIAcQ+uAwvCw+HWIlHA29B9gxarfoI/uEdGwVmfRm3YyOZSe3f9cwgDdMzurUlkQ8LSQMSv4yGHRuFPZ8r++xAAgQHK3ZeeKltdVLilwm0Pcpw0Ak2zRoxIWgFC2Wt4TLzm52xGI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=185.176.79.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.18.224.83]) by frasgout.his.huawei.com (SkyGuard) with ESMTPS id 4drD231SJ5zHnGdQ; Tue, 13 Jan 2026 23:39:23 +0800 (CST) Received: from dubpeml100005.china.huawei.com (unknown [7.214.146.113]) by mail.maildlp.com (Postfix) with ESMTPS id 63C1A40572; Tue, 13 Jan 2026 23:39:41 +0800 (CST) Received: from localhost (10.203.177.15) by dubpeml100005.china.huawei.com (7.214.146.113) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.36; Tue, 13 Jan 2026 15:39:40 +0000 Date: Tue, 13 Jan 2026 15:39:38 +0000 From: Jonathan Cameron To: Ben Horgan CC: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Zeng Heng Subject: Re: [PATCH v3 41/47] arm_mpam: Generate a configuration for min controls Message-ID: <20260113153938.00007d6e@huawei.com> In-Reply-To: <20260112165914.4086692-42-ben.horgan@arm.com> References: <20260112165914.4086692-1-ben.horgan@arm.com> <20260112165914.4086692-42-ben.horgan@arm.com> X-Mailer: Claws Mail 4.3.0 (GTK 3.24.42; x86_64-w64-mingw32) Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: lhrpeml100012.china.huawei.com (7.191.174.184) To dubpeml100005.china.huawei.com (7.214.146.113) On Mon, 12 Jan 2026 16:59:08 +0000 Ben Horgan wrote: > From: James Morse > > MPAM supports a minimum and maximum control for memory bandwidth. The > purpose of the minimum control is to give priority to tasks that are below > their minimum value. Resctrl only provides one value for the bandwidth > configuration, which is used for the maximum. > > The minimum control is always programmed to zero on hardware that supports > it. > > Generate a minimum bandwidth value that is 5% lower than the value provided > by resctrl. This means tasks that are not receiving their target bandwidth > can be prioritised by the hardware. > > For component reset reuse the same calculation so that the default is a > value resctrl can set. > > CC: Zeng Heng > Signed-off-by: James Morse > Signed-off-by: Ben Horgan I'm interested to see how this plays out as a default choice vs what people elect to run. Seems harmless to start with this. Reviewed-by: Jonathan Cameron