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 8200CEDEC50 for ; Wed, 13 Sep 2023 13:12:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Subject:CC:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=EmCPZuwG/eY4oqViyB29CpbgQvpFdp3B/86Zn2cSQ0w=; b=jbCfJVEU9nyp0b YRr566DQjl8F/3xkaH6tYhjziE/Z6NbvZDEm2DthodACYvVONhp81lKLCtdmXgxi98ota9dpfcIr3 2qdrOgow9IEBTb/EHfWbFiur/75gdYKK7dKT7yilvOp+NHPNsLo/LWAATB2Wz4yXQla9d7zhCULiz GJmA5Sq0f2WZtRicoucoywkOOyVbxqWZ4zmkXJyXDlzU9JdYAgJ+/fvTA+HRAKM0CgXBignxA+yKZ uxfBIQLPjIEBKJpxyrqehk6qUw6HGi1ama+nAat9QT0U4q7tpQajR3g++oXcG4DdxcpC0PR7JXxOd 7PvfCTtI/wt0nMuN6e1w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qgPem-005x8c-2J; Wed, 13 Sep 2023 13:11:48 +0000 Received: from frasgout.his.huawei.com ([185.176.79.56]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qgPej-005x7Y-1Z for linux-arm-kernel@lists.infradead.org; Wed, 13 Sep 2023 13:11:46 +0000 Received: from lhrpeml500005.china.huawei.com (unknown [172.18.147.206]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Rm11t0dbbz6D99p; Wed, 13 Sep 2023 21:06:58 +0800 (CST) Received: from localhost (10.202.227.76) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.31; Wed, 13 Sep 2023 14:11:37 +0100 Date: Wed, 13 Sep 2023 14:11:36 +0100 From: Jonathan Cameron To: Jinhui Guo , CC: , , , , Subject: Re: [PATCH] arm64: cpufeature: Expose the real mpidr value to EL0 Message-ID: <20230913141136.00006a47@Huawei.com> In-Reply-To: <20230913105133.2902-1-guojinhui.liam@bytedance.com> References: <20230912115116.000049b0@Huawei.com> <20230913105133.2902-1-guojinhui.liam@bytedance.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) MIME-Version: 1.0 X-Originating-IP: [10.202.227.76] X-ClientProxiedBy: lhrpeml500005.china.huawei.com (7.191.163.240) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230913_061145_666233_BFF940C5 X-CRM114-Status: GOOD ( 12.90 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, 13 Sep 2023 18:51:33 +0800 Jinhui Guo wrote: > > As a follow up question, is there some information that is missing from > > current topology description? (there is lots missing but I'm curious > > as to what might matter for your use case!) > > We want to know the infomation about dies to advoid memroy accessing > across dies (some settings like 2 numa per die). The NUMA access characteristics should give you the info you want - it's the variation in latency and bandwidth between dies that matters, not that they are dies. If you got really bad access characteristics across a die that info would be equally useful. I think it is not that this is a die that matters, but rather that there are groups of Numa nodes with relatively small differences in access characteristics, then others with much larger variation (and I assume a layer above that which is inter socket which is even worse). The info is in HMAT, but the kernel presentation of HMAT is rather limited currently - so you may want to look at extending what is visible in sysfs from that table. Thanks, Jonathan > > thanks, > > Jinhui Guo > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel