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 C684D221F26; Tue, 7 Jul 2026 08:35:58 +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=1783413359; cv=none; b=eR7G+JsfRQdrXztmzsCoHlZB9Qjlb7oQ+dLDWeCMm5xRmP+iXwq4+Fb0mZloKKxOAMnwrqiS8OfpMP4xserMGC8fiN3/CHvNAf5PCOHW1JTSFb0SlW+uwFelXJWZ2OBWTjqc33vYLiUmxtByYHbObnGZdXWdYxPBjo0tcHYlhLQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783413359; c=relaxed/simple; bh=u3RlVTowKqTUJwgRzp3SA9YrCrbi3lk5EF2OOQEph4A=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Y/+0XpgI6mXOPjWBWhBQd5hrN/51Flp2HI1g6B+c5MRo9dtef+jw/6vJA8Wk97HeegyPWqndT1YRh4ht4/9QtUQfk+f4khLylNLIaCjVwuSrpQVlvh5RDt/Dh2zWKGv7FagrTzS5Cy6GzJgnMSPjNUuPNKlqvKwxnQolhT+bMNs= 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; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=RQ6Y0C2W; 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 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="RQ6Y0C2W" 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 DDBCF2379; Tue, 7 Jul 2026 01:35:48 -0700 (PDT) Received: from [10.2.212.8] (e134344.arm.com [10.2.212.8]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 37E5E3F85F; Tue, 7 Jul 2026 01:35:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1783413353; bh=u3RlVTowKqTUJwgRzp3SA9YrCrbi3lk5EF2OOQEph4A=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=RQ6Y0C2Wptt8NGN3y917WJAMNoPF9+mkViw0HKaM+pw37cU5w3GN2wq/zSyBfkaPQ douyxLGmNgkVyeJzYO7uti42uJmucdVttqpysAYMQ9G+LnV4dh7WrDzO9Bbla8RDM6 pN19sG4XRgGtc5XGE2xYWPrh/LDVrceOe3vBzEcs= Message-ID: Date: Tue, 7 Jul 2026 09:35:49 +0100 Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Thunderbird Daily Subject: Re: [PATCH v4 2/3] arm_mpam: resctrl: Add pass-through resctrl_arch_preconvert_bw() To: Reinette Chatre Cc: james.morse@arm.com, fenghuay@nvidia.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, corbet@lwn.net, x86@kernel.org, linux-doc@vger.kernel.org, dave.martin@arm.com References: <20260706160639.2136674-1-ben.horgan@arm.com> <20260706160639.2136674-3-ben.horgan@arm.com> <4c520a28-9a72-4abd-8e5b-654a312c92fd@intel.com> Content-Language: en-US From: Ben Horgan In-Reply-To: <4c520a28-9a72-4abd-8e5b-654a312c92fd@intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Reinette, On 7/6/26 22:33, Reinette Chatre wrote: > Hi Ben, > > On 7/6/26 9:06 AM, Ben Horgan wrote: >> resctrl rounds up the percentage value of the MBA based on the bw_gran. As >> MPAM uses a binary fixed point fraction format for MBA rather than a >> decimal percentage, this introduces rounding errors. >> >> Without this additional rounding, if the user reads the value in an MB >> schema and then writes it back to the schema, the value in hardware won't >> change. However, with this additional rounding, this guarantee is broken >> for systems with mbw_wd < 7. >> >> resctrl is introducing resctrl_arch_preconvert_bw() to allow the arch code >> to specify the conversion resctrl does to the user-provided bandwidth >> value. Add the MPAM version of resctrl_arch_preconvert_bw(). This does no >> conversion. >> >> Signed-off-by: Ben Horgan >> Reviewed-by: Reinette Chatre >> > > Unfortunately the "---" separator is missing here. Another silly mistake.. sorry about that. I've corrected locally and will send a respin in a day or two. Thanks, Ben > >> Changes since v3: >> Parameter order switch (Reinette) >> Add Reinette's R-b >> --- > Reinette