Re: [RFC v2 1/7] hw/core: Make CPU topology enumeration arch-agnostic

Markus Armbruster
2024-06-03T12:25:44Z

Zhao Liu <zhao1.liu@intel.com> writes:

> Cache topology needs to be defined based on CPU topology levels. Thus,
> define CPU topology enumeration in qapi/machine.json to make it generic
> for all architectures.
>
> To match the general topology naming style, rename CPU_TOPO_LEVEL_SMT
> and CPU_TOPO_LEVEL_PACKAGE to CPU_TOPO_LEVEL_THREAD and
> CPU_TOPO_LEVEL_SOCKET.
>
> Also, enumerate additional topology levels for non-i386 arches, and add
> helpers for topology enumeration and string conversion.
>
> Signed-off-by: Zhao Liu <zhao1.liu@intel.com>

[...]

> diff --git a/qapi/machine.json b/qapi/machine.json
> index bce6e1bbc412..7ac5a05bb9c9 100644
> --- a/qapi/machine.json
> +++ b/qapi/machine.json
> @@ -1667,6 +1667,46 @@
> '*reboot-timeout': 'int',
> '*strict': 'bool' } }
>
> +##
> +# @CPUTopoLevel:

I understand you're moving existing enum CPUTopoLevel into the QAPI
schema. I think the idiomatic QAPI name would be CpuTopologyLevel.
Would you be willing to rename it, or would that be too much churn?

> +#
> +# An enumeration of CPU topology levels.
> +#
> +# @invalid: Invalid topology level, used as a placeholder.
> +#
> +# @thread: thread level, which would also be called SMT level or logical
> +# processor level. The @threads option in -smp is used to configure
> +# the topology of this level.
> +#
> +# @core: core level. The @cores option in -smp is used to configure the
> +# topology of this level.
> +#
> +# @module: module level. The @modules option in -smp is used to
> +# configure the topology of this level.
> +#
> +# @cluster: cluster level. The @clusters option in -smp is used to
> +# configure the topology of this level.
> +#
> +# @die: die level. The @dies option in -smp is used to configure the
> +# topology of this level.
> +#
> +# @socket: socket level, which would also be called package level. The
> +# @sockets option in -smp is used to configure the topology of this
> +# level.
> +#
> +# @book: book level. The @books option in -smp is used to configure the
> +# topology of this level.
> +#
> +# @drawer: drawer level. The @drawers option in -smp is used to
> +# configure the topology of this level.

docs/devel/qapi-code-gen.rst section Documentation markup:

For legibility, wrap text paragraphs so every line is at most 70
characters long.

Separate sentences with two spaces.

> +#
> +# Since: 9.1
> +##
> +{ 'enum': 'CPUTopoLevel',
> + 'prefix': 'CPU_TOPO_LEVEL',
> + 'data': [ 'invalid', 'thread', 'core', 'module', 'cluster',
> + 'die', 'socket', 'book', 'drawer' ] }
> +
> ##
> # @SMPConfiguration:
> # …