From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sudeep Holla Subject: Re: [RFC PATCH] Documentation: DT: arm: Add topology property to define package boundaries Date: Mon, 22 Jan 2018 17:29:20 +0000 Message-ID: References: <20180122171534.7681-1-lorenzo.pieralisi@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180122171534.7681-1-lorenzo.pieralisi-5wv7dgnIgG8@public.gmane.org> Content-Language: en-US Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Lorenzo Pieralisi , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: Sudeep Holla , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Rob Herring , Jeremy Linton , Morten Rasmussen , Mark Rutland List-Id: devicetree@vger.kernel.org On 22/01/18 17:15, Lorenzo Pieralisi wrote: > 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. > > As opposed to the ACPI topology description ([1], PPTT table), this > hierarchical representation of clusters does not allow to describe what > topology level actually represents the physical package boundary, which > is a key piece of information to be used by an operating system to > optimize resource allocation and scheduling. > > Define an optional, backward compatible boolean property for cluster > nodes that, by reusing the ACPI nomenclature, add to the ARM DT > topological description a binding to define what cluster level > represents a physical package boundary. > > [1] http://www.uefi.org/sites/default/files/resources/ACPI_6_2.pdf > > Signed-off-by: Lorenzo Pieralisi > Cc: Rob Herring > Cc: Sudeep Holla > Cc: Jeremy Linton > Cc: Morten Rasmussen > Cc: Mark Rutland > --- > Documentation/devicetree/bindings/arm/topology.txt | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/Documentation/devicetree/bindings/arm/topology.txt b/Documentation/devicetree/bindings/arm/topology.txt > index de9eb0486630..8e78d76b0671 100644 > --- a/Documentation/devicetree/bindings/arm/topology.txt > +++ b/Documentation/devicetree/bindings/arm/topology.txt > @@ -109,6 +109,15 @@ Bindings for cluster/cpu/thread nodes are defined as follows: > The cluster node name must be "clusterN" as described in 2.1 above. > A cluster node can not be a leaf node. > > + Properties for cluster nodes: > + > + - physical-package > + Usage: optional > + Value type: IIUC, value type must be specified as boolean in this case. > + Definition: if present the cluster node represents the > + boundary of a physical package, whether socketed > + or surface mounted. > + > A cluster node's child nodes must be: > > - one or more cluster nodes; or > Otherwise looks good to me. -- Regards, Sudeep -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html