Dear All:

Got it.

Thank you very much.

Thanks

 

From: Laszlo Ersek

Date: 2021-02-22 18:39

To: devel; tigerliu

Subject: Re: [edk2-devel] MP Services Protocol : Support Hyper threading or not

On 02/22/21 08:08, Tiger Liu(BJ-RD) wrote:

> Dear All:

> I have a question about MP Services Protocol.

> Does it support Hyper-threading technology?

>

> For example:

> A Quad-cores CPU(with HT feature support), actually it is equal to 8 logical cores.

> Take assumption 8 logical cores are all healthy and being enabled.

>

> So:

>

> 1.      Will EFI_MP_SERVICES_PROTOCOL.GetNumberOfProcessors()return total 8 logical processor cores?

>

> 2.      Will EFI_MP_SERVICES_PROTOCOL.StartupAllAPs() make all 8 logical cores do some tasks simultaneously?

 

My understanding is "yes", to both questions. Most of the MP stuff deals

with "logical processors".

 

 

BTW, if you check the EFI_MP_SERVICES_GET_PROCESSOR_INFO prototype, it

outputs EFI_PROCESSOR_INFORMATION. The latter has the following fields:

 

  EFI_CPU_PHYSICAL_LOCATION      Location;

  EXTENDED_PROCESSOR_INFORMATION ExtendedInformation;

 

The former gives you a package/core/thread identification for a

particular processor number. The latter (optionally) provides a 6-level

description (package / module / tile / die / core / thread). In each

information structure, "logical thread" is the finest granularity

information.

 

hth

Laszlo