Re: [PATCH 1/8] hmat acpi: Don't require initiator value in -numa

[Liu, Jingqi]

On 7/11/2022 6:44 PM, Hesham Almatary via wrote:
> From: Brice Goglin <Brice.Goglin@inria.fr>
>
> The "Memory Proximity Domain Attributes" structure of the ACPI HMAT
> has a "Processor Proximity Domain Valid" flag that is currently
> always set because Qemu -numa requires an initiator=X value
> when hmat=on. Unsetting this flag allows to create more complex
> memory topologies by having multiple best initiators for a single
> memory target.

Do you mean the memory-only numa node requires an initiator=X value ?

It would be better if you can explicitly provide cases in the description

for creating more complex memory topologies without initiator=X.

Thanks,

Jingqi

> This patch allows -numa without initiator=X when hmat=on by keeping
> the default value MAX_NODES in numa_state->nodes[i].initiator.
> All places reading numa_state->nodes[i].initiator already check
> whether it's different from MAX_NODES before using it.
>
> Tested with
> qemu-system-x86_64 -accel kvm \
>   -machine pc,hmat=on \
>   -drive if=pflash,format=raw,file=./OVMF.fd \
>   -drive media=disk,format=qcow2,file=efi.qcow2 \
>   -smp 4 \
>   -m 3G \
>   -object memory-backend-ram,size=1G,id=ram0 \
>   -object memory-backend-ram,size=1G,id=ram1 \
>   -object memory-backend-ram,size=1G,id=ram2 \
>   -numa node,nodeid=0,memdev=ram0,cpus=0-1 \
>   -numa node,nodeid=1,memdev=ram1,cpus=2-3 \
>   -numa node,nodeid=2,memdev=ram2 \
>   -numa 
> hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=10
>  \
>   -numa 
> hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=10485760
>  \
>   -numa 
> hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=20
>  \
>   -numa 
> hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=5242880
>  \
>   -numa 
> hmat-lb,initiator=0,target=2,hierarchy=memory,data-type=access-latency,latency=30
>  \
>   -numa 
> hmat-lb,initiator=0,target=2,hierarchy=memory,data-type=access-bandwidth,bandwidth=1048576
>  \
>   -numa 
> hmat-lb,initiator=1,target=0,hierarchy=memory,data-type=access-latency,latency=20
>  \
>   -numa 
> hmat-lb,initiator=1,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=5242880
>  \
>   -numa 
> hmat-lb,initiator=1,target=1,hierarchy=memory,data-type=access-latency,latency=10
>  \
>   -numa 
> hmat-lb,initiator=1,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=10485760
>  \
>   -numa 
> hmat-lb,initiator=1,target=2,hierarchy=memory,data-type=access-latency,latency=30
>  \
>   -numa 
> hmat-lb,initiator=1,target=2,hierarchy=memory,data-type=access-bandwidth,bandwidth=1048576
> which reports NUMA node2 at same distance from both node0 and node1 as seen in 
> lstopo:
> Machine (2966MB total) + Package P#0
>    NUMANode P#2 (979MB)
>    Group0
>      NUMANode P#0 (980MB)
>      Core P#0 + PU P#0
>      Core P#1 + PU P#1
>    Group0
>      NUMANode P#1 (1007MB)
>      Core P#2 + PU P#2
>      Core P#3 + PU P#3
>
> Before this patch, we had to add ",initiator=X" to "-numa 
> node,nodeid=2,memdev=ram2".
> The lstopo output difference between initiator=1 and no initiator is:
> @@ -1,10 +1,10 @@
>   Machine (2966MB total) + Package P#0
> +  NUMANode P#2 (979MB)
>     Group0
>       NUMANode P#0 (980MB)
>       Core P#0 + PU P#0
>       Core P#1 + PU P#1
>     Group0
>       NUMANode P#1 (1007MB)
> -    NUMANode P#2 (979MB)
>       Core P#2 + PU P#2
>       Core P#3 + PU P#3
>
> Corresponding changes in the HMAT MPDA structure:
> @@ -49,10 +49,10 @@
>   [078h 0120   2]               Structure Type : 0000 [Memory Proximity Domain 
> Attributes]
>   [07Ah 0122   2]                     Reserved : 0000
>   [07Ch 0124   4]                       Length : 00000028
> -[080h 0128   2]        Flags (decoded below) : 0001
> -            Processor Proximity Domain Valid : 1
> +[080h 0128   2]        Flags (decoded below) : 0000
> +            Processor Proximity Domain Valid : 0
>   [082h 0130   2]                    Reserved1 : 0000
> -[084h 0132   4] Attached Initiator Proximity Domain : 00000001
> +[084h 0132   4] Attached Initiator Proximity Domain : 00000080
>   [088h 0136   4]      Memory Proximity Domain : 00000002
>   [08Ch 0140   4]                    Reserved2 : 00000000
>   [090h 0144   8]                    Reserved3 : 0000000000000000
>
> Final HMAT SLLB structures:
> [0A0h 0160   2]               Structure Type : 0001 [System Locality Latency 
> and Bandwidth Information]
> [0A2h 0162   2]                     Reserved : 0000
> [0A4h 0164   4]                       Length : 00000040
> [0A8h 0168   1]        Flags (decoded below) : 00
>                              Memory Hierarchy : 0
> [0A9h 0169   1]                    Data Type : 00
> [0AAh 0170   2]                    Reserved1 : 0000
> [0ACh 0172   4] Initiator Proximity Domains # : 00000002
> [0B0h 0176   4]   Target Proximity Domains # : 00000003
> [0B4h 0180   4]                    Reserved2 : 00000000
> [0B8h 0184   8]              Entry Base Unit : 0000000000002710
> [0C0h 0192   4] Initiator Proximity Domain List : 00000000
> [0C4h 0196   4] Initiator Proximity Domain List : 00000001
> [0C8h 0200   4] Target Proximity Domain List : 00000000
> [0CCh 0204   4] Target Proximity Domain List : 00000001
> [0D0h 0208   4] Target Proximity Domain List : 00000002
> [0D4h 0212   2]                        Entry : 0001
> [0D6h 0214   2]                        Entry : 0002
> [0D8h 0216   2]                        Entry : 0003
> [0DAh 0218   2]                        Entry : 0002
> [0DCh 0220   2]                        Entry : 0001
> [0DEh 0222   2]                        Entry : 0003
>
> [0E0h 0224   2]               Structure Type : 0001 [System Locality Latency 
> and Bandwidth Information]
> [0E2h 0226   2]                     Reserved : 0000
> [0E4h 0228   4]                       Length : 00000040
> [0E8h 0232   1]        Flags (decoded below) : 00
>                              Memory Hierarchy : 0
> [0E9h 0233   1]                    Data Type : 03
> [0EAh 0234   2]                    Reserved1 : 0000
> [0ECh 0236   4] Initiator Proximity Domains # : 00000002
> [0F0h 0240   4]   Target Proximity Domains # : 00000003
> [0F4h 0244   4]                    Reserved2 : 00000000
> [0F8h 0248   8]              Entry Base Unit : 0000000000000001
> [100h 0256   4] Initiator Proximity Domain List : 00000000
> [104h 0260   4] Initiator Proximity Domain List : 00000001
> [108h 0264   4] Target Proximity Domain List : 00000000
> [10Ch 0268   4] Target Proximity Domain List : 00000001
> [110h 0272   4] Target Proximity Domain List : 00000002
> [114h 0276   2]                        Entry : 000A
> [116h 0278   2]                        Entry : 0005
> [118h 0280   2]                        Entry : 0001
> [11Ah 0282   2]                        Entry : 0005
> [11Ch 0284   2]                        Entry : 000A
> [11Eh 0286   2]                        Entry : 0001
>
> Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>
> ---
>   hw/core/machine.c | 4 +---
>   1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/hw/core/machine.c b/hw/core/machine.c
> index a673302cce..d4d7e77401 100644
> --- a/hw/core/machine.c
> +++ b/hw/core/machine.c
> @@ -1173,9 +1173,7 @@ static void numa_validate_initiator(NumaState *numa_state)
>   
>       for (i = 0; i < numa_state->num_nodes; i++) {
>           if (numa_info[i].initiator == MAX_NODES) {
> -            error_report("The initiator of NUMA node %d is missing, use "
> -                         "'-numa node,initiator' option to declare it", i);
> -            exit(1);
> +            continue;
>           }
>   
>           if (!numa_info[numa_info[i].initiator].present) {