From nobody Sun Feb 8 19:25:02 2026 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 33A1817C8; Sun, 24 Mar 2024 03:07:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711249642; cv=none; b=Tj5zpqUgA8uhMlb9YLbyrmNwNGxiTasTQqlwBAvYdqGm6wbsRiA95GBvPvpmG9aQLHC3kRvSXozzq9c/dvoabcVL8U1ir4Um50yiJbCUWPjpFsoGuYT4WencgLWQT6gojxbKGFrtJdiHvc2/yTrzOyGzAqWVGCKbtApromQr4OE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711249642; c=relaxed/simple; bh=8SqvdGYhJHvygOI7smYCwc3G+VPv6sH4BF+CBTZjXrw=; h=Date:From:To:Subject:Cc:In-Reply-To:References:MIME-Version: Message-ID:Content-Type; b=GENtqvPF7/k6l/yzGhcQ9y1dQN5uXZ8yIg0Oov+RBnx5F8BZbQthXm0lXTuizC8isAO9HpRr036b9t+bVwaD2aEUem4/pp4LaxyOpJBl1C6ak/jo0lEbSaYU39IljJRSOKl155cJ9uaCJJqFWTHDRZ24u9+W/BZZMI9FJdkZiKM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=3bK5VAlO; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=OB8GVwkw; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="3bK5VAlO"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="OB8GVwkw" Date: Sun, 24 Mar 2024 03:07:17 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1711249639; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=j7BXDn66DR8wcemUgRzv2AAibAH17t9P9tPvKM4Ia6E=; b=3bK5VAlOjluwX4Pc7rgvD9tor2Ta/U5t5lymekGba0Ju4Qp/TY3frgdzy+1KAPSnehBH+m nj4JJfDaSyrSs4ZwTSMg3BzL9Ygciip5ThUahkNPlldoAJ2FZiGsV8mC8bCNMO1JoCG0iu I0pH4amB6rN1rvaTcPiTCB2m6uZFJWNnluiTUssEuaOUunvF6hlZ6dEKCgncO0txnjsswS OeoMW/yCc/Gvjsr5RCmPv2ZDEwlEzvYe+sEk1Bob44zIhtMg5u4Cr6iggVBbVs/DTiYb73 sfLxfP9vXsCrL/LV8upShQrR/Dx7kGATSOHluokxmyjzuN2Wczhm/KSd9PliwQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1711249639; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=j7BXDn66DR8wcemUgRzv2AAibAH17t9P9tPvKM4Ia6E=; b=OB8GVwkwUNxpaDnFpEmjTspGKapSyy2EN9Cj8wJ2Lvmp2VnrXtd8zQEBTLmm4HgY2fk0r4 DPi+/xcQ5++gGHDQ== From: "tip-bot2 for Tony Luck" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/urgent] Documentation/x86: Document that resctrl bandwidth control units are MiB Cc: Tony Luck , Ingo Molnar , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20240322182016.196544-1-tony.luck@intel.com> References: <20240322182016.196544-1-tony.luck@intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <171124963792.10875.12035829539103388690.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Precedence: bulk Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The following commit has been merged into the x86/urgent branch of tip: Commit-ID: a8ed59a3a8de2648e69dd5936f5771ac4c92d085 Gitweb: https://git.kernel.org/tip/a8ed59a3a8de2648e69dd5936f5771ac4= c92d085 Author: Tony Luck AuthorDate: Fri, 22 Mar 2024 11:20:15 -07:00 Committer: Ingo Molnar CommitterDate: Sun, 24 Mar 2024 03:58:43 +01:00 Documentation/x86: Document that resctrl bandwidth control units are MiB The memory bandwidth software controller uses 2^20 units rather than 10^6. See mbm_bw_count() which computes bandwidth using the "SZ_1M" Linux define for 0x00100000. Update the documentation to use MiB when describing this feature. It's too late to fix the mount option "mba_MBps" as that is now an established user interface. Signed-off-by: Tony Luck Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20240322182016.196544-1-tony.luck@intel.com --- Documentation/arch/x86/resctrl.rst | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/Documentation/arch/x86/resctrl.rst b/Documentation/arch/x86/re= sctrl.rst index a6279df..3712d81 100644 --- a/Documentation/arch/x86/resctrl.rst +++ b/Documentation/arch/x86/resctrl.rst @@ -45,7 +45,7 @@ mount options are: Enable code/data prioritization in L2 cache allocations. "mba_MBps": Enable the MBA Software Controller(mba_sc) to specify MBA - bandwidth in MBps + bandwidth in MiBps "debug": Make debug files accessible. Available debug files are annotated with "Available only with debug option". @@ -526,7 +526,7 @@ threads start using more cores in an rdtgroup, the actu= al bandwidth may increase or vary although user specified bandwidth percentage is same. =20 In order to mitigate this and make the interface more user friendly, -resctrl added support for specifying the bandwidth in MBps as well. The +resctrl added support for specifying the bandwidth in MiBps as well. The kernel underneath would use a software feedback mechanism or a "Software Controller(mba_sc)" which reads the actual bandwidth using MBM counters and adjust the memory bandwidth percentages to ensure:: @@ -573,13 +573,13 @@ Memory b/w domain is L3 cache. =20 MB:=3Dbandwidth0;=3Dbandwidth1;... =20 -Memory bandwidth Allocation specified in MBps +Memory bandwidth Allocation specified in MiBps --------------------------------------------- =20 Memory bandwidth domain is L3 cache. :: =20 - MB:=3Dbw_MBps0;=3Dbw_MBps1;... + MB:=3Dbw_MiBps0;=3Dbw_MiBps1;... =20 Slow Memory Bandwidth Allocation (SMBA) ---------------------------------------