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[209.132.180.67]) by mx.google.com with ESMTP id b89si3363824pfj.207.2018.11.29.15.09.23; Thu, 29 Nov 2018 15:09:23 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=fail header.i=@wdc.com header.s=dkim.wdc.com header.b=Jg1vHUMR; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=wdc.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727647AbeK3KQ1 (ORCPT + 32 others); Fri, 30 Nov 2018 05:16:27 -0500 Received: from esa6.hgst.iphmx.com ([216.71.154.45]:43698 "EHLO esa6.hgst.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726793AbeK3KQ1 (ORCPT ); Fri, 30 Nov 2018 05:16:27 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=wdc.com; i=@wdc.com; q=dns/txt; s=dkim.wdc.com; t=1543532959; x=1575068959; h=from:to:subject:date:message-id:in-reply-to:references; bh=AYMd4SewaG0Q02XlqjXMaFjc2G4H12uRnUc4XgGDUec=; b=Jg1vHUMRfYIHATqJtY6jYRtPSnkLbbraOFEeLRKfAzkfVVdiv2GsVP6+ 1INUxz5jwYiuHh9jfFYRT6kfaYsbd9B9AfO5T7SdZpvtceEnUR+Ma45xM PJrUUCvzINWQBd7PrCmjbpMIu7Iqpciwd3Qu29oidI/0VNn/gbak4rUs+ v42QtM3fzNTFwWZgKAN1iwfb4ZlYishGt7aJQ0RX+doDxa0VCTeEsE+t3 eC2AVIn4nD+HNZYpX7IUoog3vQQ86qGB/XRWrbq961DgkHePMP5+bO2BN gTwCvVxIUh2USiabKiyuGT63TMkkqVrkloPuDXKSvKEyUe2dDtGJ12kvR w==; X-IronPort-AV: E=Sophos;i="5.56,296,1539619200"; d="scan'208";a="97183854" Received: from h199-255-45-15.hgst.com (HELO uls-op-cesaep02.wdc.com) ([199.255.45.15]) by ob1.hgst.iphmx.com with ESMTP; 30 Nov 2018 07:09:18 +0800 Received: from uls-op-cesaip02.wdc.com ([10.248.3.37]) by uls-op-cesaep02.wdc.com with ESMTP; 29 Nov 2018 14:52:14 -0800 Received: from jedi-01.sdcorp.global.sandisk.com (HELO jedi-01.int.fusionio.com) ([10.11.143.218]) by uls-op-cesaip02.wdc.com with ESMTP; 29 Nov 2018 15:09:19 -0800 From: Atish Patra To: linux-kernel@vger.kernel.org, atish.patra@wdc.com Subject: [RFT PATCH 1/4] Documentation: DT: arm: add support for sockets defining package boundaries Date: Thu, 29 Nov 2018 15:09:14 -0800 Message-Id: <1543532957-22661-2-git-send-email-atish.patra@wdc.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1543532957-22661-1-git-send-email-atish.patra@wdc.com> References: <1543532957-22661-1-git-send-email-atish.patra@wdc.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sudeep Holla The current ARM DT topology description provides the operating system with a topological view of the system that is based on leaf nodes representing either cores or threads (in an SMT system) and a hierarchical set of cluster nodes that creates a hierarchical topology view of how those cores and threads are grouped. However this hierarchical representation of clusters does not allow to describe what topology level actually represents the physical package or the socket boundary, which is a key piece of information to be used by an operating system to optimize resource allocation and scheduling. Lets add a new "socket" node type in the cpu-map node to describe the same. Signed-off-by: Sudeep Holla --- Documentation/devicetree/bindings/arm/topology.txt | 52 ++++++++++++++++------ 1 file changed, 39 insertions(+), 13 deletions(-) -- 2.7.4 diff --git a/Documentation/devicetree/bindings/arm/topology.txt b/Documentation/devicetree/bindings/arm/topology.txt index de9eb048..66848355 100644 --- a/Documentation/devicetree/bindings/arm/topology.txt +++ b/Documentation/devicetree/bindings/arm/topology.txt @@ -9,6 +9,7 @@ ARM topology binding description In an ARM system, the hierarchy of CPUs is defined through three entities that are used to describe the layout of physical CPUs in the system: +- socket - cluster - core - thread @@ -63,21 +64,23 @@ nodes are listed. The cpu-map node's child nodes can be: - - one or more cluster nodes + - one or more cluster nodes or + - one or more socket nodes in a multi-socket system Any other configuration is considered invalid. -The cpu-map node can only contain three types of child nodes: +The cpu-map node can only contain 4 types of child nodes: +- socket node - cluster node - core node - thread node whose bindings are described in paragraph 3. -The nodes describing the CPU topology (cluster/core/thread) can only -be defined within the cpu-map node and every core/thread in the system -must be defined within the topology. Any other configuration is +The nodes describing the CPU topology (socket/cluster/core/thread) can +only be defined within the cpu-map node and every core/thread in the +system must be defined within the topology. Any other configuration is invalid and therefore must be ignored. =========================================== @@ -85,26 +88,44 @@ invalid and therefore must be ignored. =========================================== cpu-map child nodes must follow a naming convention where the node name -must be "clusterN", "coreN", "threadN" depending on the node type (ie -cluster/core/thread) (where N = {0, 1, ...} is the node number; nodes which -are siblings within a single common parent node must be given a unique and +must be "socketN", "clusterN", "coreN", "threadN" depending on the node type +(ie socket/cluster/core/thread) (where N = {0, 1, ...} is the node number; nodes +which are siblings within a single common parent node must be given a unique and sequential N value, starting from 0). cpu-map child nodes which do not share a common parent node can have the same name (ie same number N as other cpu-map child nodes at different device tree levels) since name uniqueness will be guaranteed by the device tree hierarchy. =========================================== -3 - cluster/core/thread node bindings +3 - socket/cluster/core/thread node bindings =========================================== -Bindings for cluster/cpu/thread nodes are defined as follows: +Bindings for socket/cluster/cpu/thread nodes are defined as follows: + +- socket node + + Description: must be declared within a cpu-map node, one node + per physical socket in the system. A system can + contain single or multiple physical socket. + The association of sockets and NUMA nodes is beyond + the scope of this bindings, please refer [2] for + NUMA bindings. + + This node is optional for a single socket system. + + The socket node name must be "socketN" as described in 2.1 above. + A socket node can not be a leaf node. + + A socket node's child nodes must be one or more cluster nodes. + + Any other configuration is considered invalid. - cluster node Description: must be declared within a cpu-map node, one node per cluster. A system can contain several layers of - clustering and cluster nodes can be contained in parent - cluster nodes. + clustering within a single physical socket and cluster + nodes can be contained in parent cluster nodes. The cluster node name must be "clusterN" as described in 2.1 above. A cluster node can not be a leaf node. @@ -164,13 +185,15 @@ Bindings for cluster/cpu/thread nodes are defined as follows: 4 - Example dts =========================================== -Example 1 (ARM 64-bit, 16-cpu system, two clusters of clusters): +Example 1 (ARM 64-bit, 16-cpu system, two clusters of clusters in a single +physical socket): cpus { #size-cells = <0>; #address-cells = <2>; cpu-map { + socket0 { cluster0 { cluster0 { core0 { @@ -253,6 +276,7 @@ cpus { }; }; }; + }; CPU0: cpu@0 { device_type = "cpu"; @@ -473,3 +497,5 @@ cpus { =============================================================================== [1] ARM Linux kernel documentation Documentation/devicetree/bindings/arm/cpus.txt +[2] Devicetree NUMA binding description + Documentation/devicetree/bindings/numa.txt