From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id ED7E010ED643 for ; Fri, 27 Mar 2026 09:50:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=8tqxcv+CemeP4RpbyqkeQRYUzEChsZ1uBxAkXmmwWKA=; b=N9S0aqLuLVe9nCPskXD38J49+f LZUONAk9CTpojNZmBmz9hE3JoMBMVDOA/Z5IRNMVf+8PjnLnBzzrUo3HzmTLOb6jprS2IWzy/QZCS yx8R0b+xopWm6//WseH4XjBZ0ZTXjH69Gl7NXGKqxrPfXx69Dc2NdMbhc3HLpV1p/AoVngTnZ8zeZ XImwE7zm+xjPMWqB7JUZ4gBQsgPTmoko7VJdYVoNVgXoH5g9DN3h8CLt6Gm/GID7SQcW5JmnBs527 EN+XKAXeru0X+YlDPQto6ricyc37bPOwzJccdXPLKaMrxZjJ3xbKx2T1sgf3eZilWvMY28siLoFiW rEZ0/ymA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w63pc-000000076yF-3O9S; Fri, 27 Mar 2026 09:50:20 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w63pZ-000000076x0-2ugE for linux-arm-kernel@lists.infradead.org; Fri, 27 Mar 2026 09:50:19 +0000 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 2E3C235A1; Fri, 27 Mar 2026 02:50:08 -0700 (PDT) Received: from [10.1.196.46] (e134344.arm.com [10.1.196.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C93E63F915; Fri, 27 Mar 2026 02:50:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1774605014; bh=xGqDhRLT0ONetRUEOxZc/0mC+NNriKwAeI+b3xAsydc=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=HSPKfmR1Pfenjxu9tz32Aa30xPUnJs4sSBngvS4tlWPwJkUE3tdq/TgCaudiHSbjL qym9k6HpuKuXmjHB9B2Hz3I0lYodoXZ+2tK8oDlzDaNy0LRQlitOVqQaV3fspGl9sc b10ZoPCZH6UOsMVPXnC/8DrsePvIxQlHBn2fYv3E= Message-ID: <599617aa-aade-4fde-9efa-79d592f1ff3f@arm.com> Date: Fri, 27 Mar 2026 09:50:09 +0000 MIME-Version: 1.0 User-Agent: Thunderbird Daily Subject: Re: [RFC PATCH v2 1/5] arm_mpam: resctrl: Pick classes for use as mbm counters To: "Shaopeng Tan (Fujitsu)" Cc: "amitsinght@marvell.com" , "baisheng.gao@unisoc.com" , "baolin.wang@linux.alibaba.com" , "carl@os.amperecomputing.com" , "dave.martin@arm.com" , "david@kernel.org" , "dfustini@baylibre.com" , "fenghuay@nvidia.com" , "gshan@redhat.com" , "james.morse@arm.com" , "jonathan.cameron@huawei.com" , "kobak@nvidia.com" , "lcherian@marvell.com" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "peternewman@google.com" , "punit.agrawal@oss.qualcomm.com" , "quic_jiles@quicinc.com" , "reinette.chatre@intel.com" , "rohit.mathew@arm.com" , "scott@os.amperecomputing.com" , "sdonthineni@nvidia.com" , "xhao@linux.alibaba.com" , "zengheng4@huawei.com" References: <20260319165540.381410-1-ben.horgan@arm.com> <20260319165540.381410-2-ben.horgan@arm.com> Content-Language: en-US From: Ben Horgan In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260327_025017_783418_A8810872 X-CRM114-Status: GOOD ( 11.39 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Shaopeng, On 3/27/26 02:53, Shaopeng Tan (Fujitsu) wrote: > Hello Ben, > > >> resctrl has two types of counters, NUMA-local and global. MPAM can only >> count global either using MSC at the L3 cache or in the memory controllers. >> When global and local equate to the same thing continue just to call it >> global. >> >> Tested-by: Shaopeng Tan >> Tested-by: Zeng Heng >> Reviewed-by: Shaopeng Tan >> Reviewed-by: Jonathan Cameron >> Signed-off-by: James Morse >> Signed-off-by: Ben Horgan > > There are environments with multiple L3 caches within a single NUMA node. > In this case, mbm_total will be the sum of traffic from all caches within that NUAM node. > Is my understanding correct? No, currently you only get mbm_total if there is single L3 cache and a single corresponding NUMA node. Rather than adding partial support by summing across numa nodes we plan to add support for memory bandwidth monitoring with NUMA node scope. Thanks, Ben > > > Best regards, > Shaopeng TAN