Re: [PATCH v3 1/4] hw/arm/virt: Consider SMP configuration in CPU topology

[wangyanan (Y)]

Hi Gavin,

On 2022/3/23 15:24, Gavin Shan wrote:
> Currently, the SMP configuration isn't considered when the CPU
> topology is populated. In this case, it's impossible to provide
> the default CPU-to-NUMA mapping or association based on the socket
> ID of the given CPU.
>
> This takes account of SMP configuration when the CPU topology
> is populated. The die ID for the given CPU isn't assigned since
> it's not supported on arm/virt machine yet. Besides, the cluster
> ID for the given CPU is assigned because it has been supported
> on arm/virt machine.
>
> Signed-off-by: Gavin Shan <gshan@redhat.com>
> ---
>   hw/arm/virt.c     | 11 +++++++++++
>   qapi/machine.json |  6 ++++--
>   2 files changed, 15 insertions(+), 2 deletions(-)
>
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index d2e5ecd234..064eac42f7 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -2505,6 +2505,7 @@ static const CPUArchIdList 
> *virt_possible_cpu_arch_ids(MachineState *ms)
>       int n;
>       unsigned int max_cpus = ms->smp.max_cpus;
>       VirtMachineState *vms = VIRT_MACHINE(ms);
> +    MachineClass *mc = MACHINE_GET_CLASS(vms);
>   
>       if (ms->possible_cpus) {
>           assert(ms->possible_cpus->len == max_cpus);
> @@ -2518,6 +2519,16 @@ static const CPUArchIdList 
> *virt_possible_cpu_arch_ids(MachineState *ms)
>           ms->possible_cpus->cpus[n].type = ms->cpu_type;
>           ms->possible_cpus->cpus[n].arch_id =
>               virt_cpu_mp_affinity(vms, n);
> +
> +        assert(!mc->smp_props.dies_supported);
> +        ms->possible_cpus->cpus[n].props.has_socket_id = true;
> +        ms->possible_cpus->cpus[n].props.socket_id =
> +            n / (ms->smp.clusters * ms->smp.cores * ms->smp.threads);
> +        ms->possible_cpus->cpus[n].props.has_cluster_id = true;
> +        ms->possible_cpus->cpus[n].props.cluster_id =
> +            n / (ms->smp.cores * ms->smp.threads);
> +        ms->possible_cpus->cpus[n].props.has_core_id = true;
> +        ms->possible_cpus->cpus[n].props.core_id = n / ms->smp.threads;
>           ms->possible_cpus->cpus[n].props.has_thread_id = true;
>           ms->possible_cpus->cpus[n].props.thread_id = n;
>       }
> diff --git a/qapi/machine.json b/qapi/machine.json
> index 42fc68403d..99c945f258 100644
> --- a/qapi/machine.json
> +++ b/qapi/machine.json
> @@ -868,10 +868,11 @@
>   # @node-id: NUMA node ID the CPU belongs to
>   # @socket-id: socket number within node/board the CPU belongs to
>   # @die-id: die number within socket the CPU belongs to (since 4.1)
> -# @core-id: core number within die the CPU belongs to
> +# @cluster-id: cluster number within die the CPU belongs to
> +# @core-id: core number within cluster the CPU belongs to
>   # @thread-id: thread number within core the CPU belongs to
>   #
> -# Note: currently there are 5 properties that could be present
> +# Note: currently there are 6 properties that could be present
>   #       but management should be prepared to pass through other
>   #       properties with device_add command to allow for future
>   #       interface extension. This also requires the filed names to be kept in
> @@ -883,6 +884,7 @@
>     'data': { '*node-id': 'int',
>               '*socket-id': 'int',
>               '*die-id': 'int',
> +            '*cluster-id': 'int',
>               '*core-id': 'int',
>               '*thread-id': 'int'
>     }
Since new cluster-id is introduced, you may want to check whether to
update machine_set_cpu_numa_node() and hmp_hotpluggable_cpus(),
accordingly, which both deal with topo-ids. If we need to update them,
it's easier to review to make the whole cluster-id introduction part
a separate patch.

Thanks,
Yanan