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

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

[Tiger Liu(BJ-RD)]

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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?

Thanks


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

[Laszlo Ersek]

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

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

[fanjianfeng]

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

All APs logical processors excute AP task, not including BSP. Acutally the answer is 7.

Jeff
 
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
 
 
 

 
 
 

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

[Tiger Liu(BJ-RD)]

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Dear All:
Got it.

Thank you very much.

Thanks
发件人: devel@edk2.groups.io <devel@edk2.groups.io> 代表 fanjianfeng@byosoft.com.cn
发送时间: 2021年2月23日 9:18
收件人: devel@edk2.groups.io; lersek <lersek@redhat.com>; Tiger Liu(BJ-RD) <TigerLiu@zhaoxin.com>
主题: Re: [edk2-devel] MP Services Protocol : Support Hyper threading or not

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

All APs logical processors excute AP task, not including BSP. Acutally the answer is 7.

Jeff

From: Laszlo Ersek<mailto:lersek@redhat.com>
Date: 2021-02-22 18:39
To: devel<mailto:devel@edk2.groups.io>; tigerliu<mailto:tigerliu@zhaoxin.com>
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









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

[Laszlo Ersek]

On 02/23/21 02:17, fanjianfeng@byosoft.com.cn wrote:
> " Will EFI_MP_SERVICES_PROTOCOL.StartupAllAPs() make all 8 logical cores do some tasks simultaneously?"
> 
> All APs logical processors excute AP task, not including BSP. Acutally the answer is 7.

Good point :)

Thanks
Laszlo

> 
> Jeff
>  
> 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
>  
>  
>  
> 
>  
>  
>  
> 
> 
> 
> 
>