Re: [Qemu-devel] [PATCH v3 4/8] Extend the command-line to provide memory latency and bandwidth information

[Igor Mammedov]

On Tue, 2 Apr 2019 12:42:37 +0800
Tao Xu <address@hidden> wrote:

> On 2/6/19 6:11 PM, Igor Mammedov wrote:
> > On Thu, 31 Jan 2019 15:16:54 +0800
> > Tao Xu <address@hidden> wrote:
> >   
> >> From: Liu Jingqi <address@hidden>
> >>
> >> Add -numa hmat-lb option to provide System Locality Latency and
> >> Bandwidth Information. These memory attributes help to build
> >> System Locality Latency and Bandwidth Information Structure(s)
> >> in ACPI Heterogeneous Memory Attribute Table (HMAT).  
> > Maybe instead of adding/using more globals since the rest of numa.c was
> > written so, it's time to introduce NumaMachine type which inherits
> > form base Machine and extends it with numa extensions.
> > 
> > You don't have to refactor all old numa code for that (just the parts
> > you use in HMAT) and later we could gradually refactor the rest of
> > numa handling.
> >   
> Hi Igor,
> 
> I am sorry for replying after so long, because I am preparing the next 
> version of patch and confusing about the implementation of NumaMachine.
> If NumaMachine inherits from Machine, and then the PCmachine and other 
> platform machine inherits from NumaMachine (Implementation a)? Or 
> PCmachine and other platform machine inherits from Machine 
> (Implementation b)?
> 
> Implementation a:             Implementation b:
> Machine                         Machine
> │                               │
> └── NumaMachine                 ├── NumaMachine
>      │                           │
>      ├── PCMachine               ├── PCMachine
>      │                           │
>      └── none-PCMachine          └── none-PCMachine

I'd imagine 'a', where none-PCMachine is arm/virt and spapr machines that
support numa today. The rest would inherit from plain Machine.

> And how about add numa.c's globals into MachineState? This may not 
> change a lot.
That's another possible way, but it's polluting generic machine with
numa specifics about which only 3-4 boards care.
From my point of view it's a bit better then globals but not much.

> Looking forward to your reply.
> 
> Tao
>