When CPU-to-NUMA association isn't explicitly provided by users,
the default on is given by mc->get_default_cpu_node_id(). However,
the CPU topology isn't fully considered in the default association
and this causes CPU topology broken warnings on booting Linux guest.
For example, the following warning messages are observed when the
Linux guest is booted with the following command lines.
/home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \
-accel kvm -machine virt,gic-version=host \
-cpu host \
-smp 6,sockets=2,cores=3,threads=1 \
-m 1024M,slots=16,maxmem=64G \
-object memory-backend-ram,id=mem0,size=128M \
-object memory-backend-ram,id=mem1,size=128M \
-object memory-backend-ram,id=mem2,size=128M \
-object memory-backend-ram,id=mem3,size=128M \
-object memory-backend-ram,id=mem4,size=128M \
-object memory-backend-ram,id=mem4,size=384M \
-numa node,nodeid=0,memdev=mem0 \
-numa node,nodeid=1,memdev=mem1 \
-numa node,nodeid=2,memdev=mem2 \
-numa node,nodeid=3,memdev=mem3 \
-numa node,nodeid=4,memdev=mem4 \
-numa node,nodeid=5,memdev=mem5
:
alternatives: patching kernel code
BUG: arch topology borken
the CLS domain not a subset of the MC domain
<the above error log repeats>
BUG: arch topology borken
the DIE domain not a subset of the NODE domain
With current implementation of mc->get_default_cpu_node_id(),
CPU#0 to CPU#5 are associated with NODE#0 to NODE#5 separately.
That's incorrect because CPU#0/1/2 should be associated with same
NUMA node because they're seated in same socket.
This fixes the issue by considering the socket ID when the default
CPU-to-NUMA association is provided in virt_possible_cpu_arch_ids().
With this applied, no more CPU topology broken warnings are seen
from the Linux guest. The 6 CPUs are associated with NODE#0/1, but
there are no CPUs associated with NODE#2/3/4/5.
Signed-off-by: Gavin Shan <gshan@redhat.com>
---
hw/arm/virt.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 064eac42f7..3286915229 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -2497,7 +2497,9 @@ virt_cpu_index_to_props(MachineState *ms, unsigned cpu_index)
static int64_t virt_get_default_cpu_node_id(const MachineState *ms, int idx)
{
- return idx % ms->numa_state->num_nodes;
+ int64_t socket_id = ms->possible_cpus->cpus[idx].props.socket_id;
+
+ return socket_id % ms->numa_state->num_nodes;
}
static const CPUArchIdList *virt_possible_cpu_arch_ids(MachineState *ms)
--
2.23.0
On 2022/3/23 15:24, Gavin Shan wrote:
> When CPU-to-NUMA association isn't explicitly provided by users,
> the default on is given by mc->get_default_cpu_node_id(). However,
s/on/one
> the CPU topology isn't fully considered in the default association
> and this causes CPU topology broken warnings on booting Linux guest.
>
> For example, the following warning messages are observed when the
> Linux guest is booted with the following command lines.
>
> /home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \
> -accel kvm -machine virt,gic-version=host \
> -cpu host \
> -smp 6,sockets=2,cores=3,threads=1 \
> -m 1024M,slots=16,maxmem=64G \
> -object memory-backend-ram,id=mem0,size=128M \
> -object memory-backend-ram,id=mem1,size=128M \
> -object memory-backend-ram,id=mem2,size=128M \
> -object memory-backend-ram,id=mem3,size=128M \
> -object memory-backend-ram,id=mem4,size=128M \
> -object memory-backend-ram,id=mem4,size=384M \
> -numa node,nodeid=0,memdev=mem0 \
> -numa node,nodeid=1,memdev=mem1 \
> -numa node,nodeid=2,memdev=mem2 \
> -numa node,nodeid=3,memdev=mem3 \
> -numa node,nodeid=4,memdev=mem4 \
> -numa node,nodeid=5,memdev=mem5
> :
> alternatives: patching kernel code
> BUG: arch topology borken
> the CLS domain not a subset of the MC domain
> <the above error log repeats>
> BUG: arch topology borken
> the DIE domain not a subset of the NODE domain
>
> With current implementation of mc->get_default_cpu_node_id(),
> CPU#0 to CPU#5 are associated with NODE#0 to NODE#5 separately.
> That's incorrect because CPU#0/1/2 should be associated with same
> NUMA node because they're seated in same socket.
>
> This fixes the issue by considering the socket ID when the default
> CPU-to-NUMA association is provided in virt_possible_cpu_arch_ids().
> With this applied, no more CPU topology broken warnings are seen
> from the Linux guest. The 6 CPUs are associated with NODE#0/1, but
> there are no CPUs associated with NODE#2/3/4/5.
>
> Signed-off-by: Gavin Shan <gshan@redhat.com>
> ---
> hw/arm/virt.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
Reviewed-by: Yanan Wang <wangyanan55@huawei.com>
Thanks,
Yanan
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index 064eac42f7..3286915229 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -2497,7 +2497,9 @@ virt_cpu_index_to_props(MachineState *ms, unsigned cpu_index)
>
> static int64_t virt_get_default_cpu_node_id(const MachineState *ms, int idx)
> {
> - return idx % ms->numa_state->num_nodes;
> + int64_t socket_id = ms->possible_cpus->cpus[idx].props.socket_id;
> +
> + return socket_id % ms->numa_state->num_nodes;
> }
>
> static const CPUArchIdList *virt_possible_cpu_arch_ids(MachineState *ms)
Hi Yanan,
On 4/2/22 10:02 AM, wangyanan (Y) wrote:
> On 2022/3/23 15:24, Gavin Shan wrote:
>> When CPU-to-NUMA association isn't explicitly provided by users,
>> the default on is given by mc->get_default_cpu_node_id(). However,
> s/on/one
Will be corrected in v5.
>> the CPU topology isn't fully considered in the default association
>> and this causes CPU topology broken warnings on booting Linux guest.
>>
>> For example, the following warning messages are observed when the
>> Linux guest is booted with the following command lines.
>>
>> /home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \
>> -accel kvm -machine virt,gic-version=host \
>> -cpu host \
>> -smp 6,sockets=2,cores=3,threads=1 \
>> -m 1024M,slots=16,maxmem=64G \
>> -object memory-backend-ram,id=mem0,size=128M \
>> -object memory-backend-ram,id=mem1,size=128M \
>> -object memory-backend-ram,id=mem2,size=128M \
>> -object memory-backend-ram,id=mem3,size=128M \
>> -object memory-backend-ram,id=mem4,size=128M \
>> -object memory-backend-ram,id=mem4,size=384M \
>> -numa node,nodeid=0,memdev=mem0 \
>> -numa node,nodeid=1,memdev=mem1 \
>> -numa node,nodeid=2,memdev=mem2 \
>> -numa node,nodeid=3,memdev=mem3 \
>> -numa node,nodeid=4,memdev=mem4 \
>> -numa node,nodeid=5,memdev=mem5
>> :
>> alternatives: patching kernel code
>> BUG: arch topology borken
>> the CLS domain not a subset of the MC domain
>> <the above error log repeats>
>> BUG: arch topology borken
>> the DIE domain not a subset of the NODE domain
>>
>> With current implementation of mc->get_default_cpu_node_id(),
>> CPU#0 to CPU#5 are associated with NODE#0 to NODE#5 separately.
>> That's incorrect because CPU#0/1/2 should be associated with same
>> NUMA node because they're seated in same socket.
>>
>> This fixes the issue by considering the socket ID when the default
>> CPU-to-NUMA association is provided in virt_possible_cpu_arch_ids().
>> With this applied, no more CPU topology broken warnings are seen
>> from the Linux guest. The 6 CPUs are associated with NODE#0/1, but
>> there are no CPUs associated with NODE#2/3/4/5.
>>
>> Signed-off-by: Gavin Shan <gshan@redhat.com>
>> ---
>> hw/arm/virt.c | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
> Reviewed-by: Yanan Wang <wangyanan55@huawei.com>
>
Thanks, will be included into v5 as I missed your comments in v4.
Please go ahead to review v5 directly.
Thanks,
Gavin
>> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
>> index 064eac42f7..3286915229 100644
>> --- a/hw/arm/virt.c
>> +++ b/hw/arm/virt.c
>> @@ -2497,7 +2497,9 @@ virt_cpu_index_to_props(MachineState *ms, unsigned cpu_index)
>> static int64_t virt_get_default_cpu_node_id(const MachineState *ms, int idx)
>> {
>> - return idx % ms->numa_state->num_nodes;
>> + int64_t socket_id = ms->possible_cpus->cpus[idx].props.socket_id;
>> +
>> + return socket_id % ms->numa_state->num_nodes;
>> }
>> static const CPUArchIdList *virt_possible_cpu_arch_ids(MachineState *ms)
>
On Wed, 23 Mar 2022 15:24:36 +0800
Gavin Shan <gshan@redhat.com> wrote:
> When CPU-to-NUMA association isn't explicitly provided by users,
> the default on is given by mc->get_default_cpu_node_id(). However,
> the CPU topology isn't fully considered in the default association
> and this causes CPU topology broken warnings on booting Linux guest.
>
> For example, the following warning messages are observed when the
> Linux guest is booted with the following command lines.
>
> /home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \
> -accel kvm -machine virt,gic-version=host \
> -cpu host \
> -smp 6,sockets=2,cores=3,threads=1 \
> -m 1024M,slots=16,maxmem=64G \
> -object memory-backend-ram,id=mem0,size=128M \
> -object memory-backend-ram,id=mem1,size=128M \
> -object memory-backend-ram,id=mem2,size=128M \
> -object memory-backend-ram,id=mem3,size=128M \
> -object memory-backend-ram,id=mem4,size=128M \
> -object memory-backend-ram,id=mem4,size=384M \
> -numa node,nodeid=0,memdev=mem0 \
> -numa node,nodeid=1,memdev=mem1 \
> -numa node,nodeid=2,memdev=mem2 \
> -numa node,nodeid=3,memdev=mem3 \
> -numa node,nodeid=4,memdev=mem4 \
> -numa node,nodeid=5,memdev=mem5
> :
> alternatives: patching kernel code
> BUG: arch topology borken
> the CLS domain not a subset of the MC domain
> <the above error log repeats>
> BUG: arch topology borken
> the DIE domain not a subset of the NODE domain
>
> With current implementation of mc->get_default_cpu_node_id(),
> CPU#0 to CPU#5 are associated with NODE#0 to NODE#5 separately.
> That's incorrect because CPU#0/1/2 should be associated with same
> NUMA node because they're seated in same socket.
>
> This fixes the issue by considering the socket ID when the default
> CPU-to-NUMA association is provided in virt_possible_cpu_arch_ids().
> With this applied, no more CPU topology broken warnings are seen
> from the Linux guest. The 6 CPUs are associated with NODE#0/1, but
> there are no CPUs associated with NODE#2/3/4/5.
>
> Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
> ---
> hw/arm/virt.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index 064eac42f7..3286915229 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -2497,7 +2497,9 @@ virt_cpu_index_to_props(MachineState *ms, unsigned cpu_index)
>
> static int64_t virt_get_default_cpu_node_id(const MachineState *ms, int idx)
> {
> - return idx % ms->numa_state->num_nodes;
> + int64_t socket_id = ms->possible_cpus->cpus[idx].props.socket_id;
> +
> + return socket_id % ms->numa_state->num_nodes;
> }
>
> static const CPUArchIdList *virt_possible_cpu_arch_ids(MachineState *ms)
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