Re: [PATCH v5 2/4] Documentation: arm64/arm: dt bindings for numa.

[Robert Richter <robert.richter@caviumnetworks.com>]

On 14.08.15 22:09:32, Ganapatrao Kulkarni wrote:
> DT bindings for numa map for memory, cores and IOs using
> arm,associativity device node property.

Arnd, Rob,

as the change below suggests the same topology syntax as already
implemented for PPC, could you take a look at this one for arm64?
Please ack the devicetree changes, assuming you are fine with it.

All other review comments are addressed so far and there are no open
issues with the patches. This would help us to further drive this
series upstream.

Many thanks,

-Robert


> Signed-off-by: Ganapatrao Kulkarni <gkulkarni@caviumnetworks.com>
> ---
>  Documentation/devicetree/bindings/arm/numa.txt | 212 +++++++++++++++++++++++++
>  1 file changed, 212 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/arm/numa.txt
> 
> diff --git a/Documentation/devicetree/bindings/arm/numa.txt b/Documentation/devicetree/bindings/arm/numa.txt
> new file mode 100644
> index 0000000..dc3ef86
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/arm/numa.txt
> @@ -0,0 +1,212 @@
> +==============================================================================
> +NUMA binding description.
> +==============================================================================
> +
> +==============================================================================
> +1 - Introduction
> +==============================================================================
> +
> +Systems employing a Non Uniform Memory Access (NUMA) architecture contain
> +collections of hardware resources including processors, memory, and I/O buses,
> +that comprise what is commonly known as a NUMA node.
> +Processor accesses to memory within the local NUMA node is generally faster
> +than processor accesses to memory outside of the local NUMA node.
> +DT defines interfaces that allow the platform to convey NUMA node
> +topology information to OS.
> +
> +==============================================================================
> +2 - arm,associativity
> +==============================================================================
> +The mapping is done using arm,associativity device property.
> +this property needs to be present in every device node which needs to to be
> +mapped to numa nodes.
> +
> +arm,associativity property is set of 32-bit integers which defines level of
> +topology and boundary in the system at which a significant difference in
> +performance can be measured between cross-device accesses within
> +a single location and those spanning multiple locations.
> +The first cell always contains the broadest subdivision within the system,
> +while the last cell enumerates the individual devices, such as an SMT thread
> +of a CPU, or a bus bridge within an SoC".
> +
> +ex:
> +	/* board 0, socket 0, cluster 0, core 0  thread 0 */
> +	arm,associativity = <0 0 0 0 0>;
> +
> +==============================================================================
> +3 - arm,associativity-reference-points
> +==============================================================================
> +This property is a set of 32-bit integers, each representing an index into
> +the arm,associativity nodes. The first integer is the most significant
> +NUMA boundary and the following are progressively less significant boundaries.
> +There can be more than one level of NUMA.
> +
> +Ex:
> +	arm,associativity-reference-points = <0 1>;
> +	The board Id(index 0) used first to calculate the associativity (node
> +	distance), then follows the  socket id(index 1).
> +
> +	arm,associativity-reference-points = <1 0>;
> +	The socket Id(index 1) used first to calculate the associativity,
> +	then follows the board id(index 0).
> +
> +	arm,associativity-reference-points = <0>;
> +	Only the board Id(index 0) used to calculate the associativity.
> +
> +	arm,associativity-reference-points = <1>;
> +	Only socket Id(index 1) used to calculate the associativity.
> +
> +==============================================================================
> +4 - Example dts
> +==============================================================================
> +
> +Example: 2 Node system consists of 2 boards and each board having one socket
> +and 8 core in each socket.
> +
> +	arm,associativity-reference-points = <0>;
> +
> +	memory@00c00000 {
> +		device_type = "memory";
> +		reg = <0x0 0x00c00000 0x0 0x80000000>;
> +		/* board 0, socket 0, no specific core */
> +		arm,associativity = <0 0 0xffff>;
> +	};
> +
> +	memory@10000000000 {
> +		device_type = "memory";
> +		reg = <0x100 0x00000000 0x0 0x80000000>;
> +		/* board 1, socket 0, no specific core */
> +		arm,associativity = <1 0 0xffff>;
> +	};
> +
> +	cpus {
> +		#address-cells = <2>;
> +		#size-cells = <0>;
> +
> +		cpu@000 {
> +			device_type = "cpu";
> +			compatible =  "arm,armv8";
> +			reg = <0x0 0x000>;
> +			enable-method = "psci";
> +			/* board 0, socket 0, core 0*/
> +			arm,associativity = <0 0 0>;
> +		};
> +		cpu@001 {
> +			device_type = "cpu";
> +			compatible =  "arm,armv8";
> +			reg = <0x0 0x001>;
> +			enable-method = "psci";
> +			arm,associativity = <0 0 1>;
> +		};
> +		cpu@002 {
> +			device_type = "cpu";
> +			compatible =  "arm,armv8";
> +			reg = <0x0 0x002>;
> +			enable-method = "psci";
> +			arm,associativity = <0 0 2>;
> +		};
> +		cpu@003 {
> +			device_type = "cpu";
> +			compatible =  "arm,armv8";
> +			reg = <0x0 0x003>;
> +			enable-method = "psci";
> +			arm,associativity = <0 0 3>;
> +		};
> +		cpu@004 {
> +			device_type = "cpu";
> +			compatible =  "arm,armv8";
> +			reg = <0x0 0x004>;
> +			enable-method = "psci";
> +			arm,associativity = <0 0 4>;
> +		};
> +		cpu@005 {
> +			device_type = "cpu";
> +			compatible =  "arm,armv8";
> +			reg = <0x0 0x005>;
> +			enable-method = "psci";
> +			arm,associativity = <0 0 5>;
> +		};
> +		cpu@006 {
> +			device_type = "cpu";
> +			compatible =  "arm,armv8";
> +			reg = <0x0 0x006>;
> +			enable-method = "psci";
> +			arm,associativity = <0 0 6>;
> +		};
> +		cpu@007 {
> +			device_type = "cpu";
> +			compatible =  "arm,armv8";
> +			reg = <0x0 0x007>;
> +			enable-method = "psci";
> +			arm,associativity = <0 0 7>;
> +		};
> +		cpu@008 {
> +			device_type = "cpu";
> +			compatible =  "arm,armv8";
> +			reg = <0x0 0x008>;
> +			enable-method = "psci";
> +			/* board 1, socket 0, core 0*/
> +			arm,associativity = <1 0 0>;
> +		};
> +		cpu@009 {
> +			device_type = "cpu";
> +			compatible =  "arm,armv8";
> +			reg = <0x0 0x009>;
> +			enable-method = "psci";
> +			arm,associativity = <1 0 1>;
> +		};
> +		cpu@00a {
> +			device_type = "cpu";
> +			compatible =  "arm,armv8";
> +			reg = <0x0 0x00a>;
> +			enable-method = "psci";
> +			arm,associativity = <0 0 2>;
> +		};
> +		cpu@00b {
> +			device_type = "cpu";
> +			compatible =  "arm,armv8";
> +			reg = <0x0 0x00b>;
> +			enable-method = "psci";
> +			arm,associativity = <1 0 3>;
> +		};
> +		cpu@00c {
> +			device_type = "cpu";
> +			compatible =  "arm,armv8";
> +			reg = <0x0 0x00c>;
> +			enable-method = "psci";
> +			arm,associativity = <1 0 4>;
> +		};
> +		cpu@00d {
> +			device_type = "cpu";
> +			compatible =  "arm,armv8";
> +			reg = <0x0 0x00d>;
> +			enable-method = "psci";
> +			arm,associativity = <1 0 5>;
> +		};
> +		cpu@00e {
> +			device_type = "cpu";
> +			compatible =  "arm,armv8";
> +			reg = <0x0 0x00e>;
> +			enable-method = "psci";
> +			arm,associativity = <1 0 6>;
> +		};
> +		cpu@00f {
> +			device_type = "cpu";
> +			compatible =  "arm,armv8";
> +			reg = <0x0 0x00f>;
> +			enable-method = "psci";
> +			arm,associativity = <1 0 7>;
> +		};
> +	};
> +
> +	pcie0: pcie0@0x8480,00000000 {
> +		compatible = "arm,armv8";
> +		device_type = "pci";
> +		bus-range = <0 255>;
> +		#size-cells = <2>;
> +		#address-cells = <3>;
> +		reg = <0x8480 0x00000000 0 0x10000000>;  /* Configuration space */
> +		ranges = <0x03000000 0x8010 0x00000000 0x8010 0x00000000 0x70 0x00000000>; /* mem ranges */
> +		/* board 0, socket 0, pci bus 0*/
> +		arm,associativity = <0 0 0>;
> +        };
> -- 
> 1.8.1.4
> 
> 
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