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

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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[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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CONFIDENTIAL NOTE:
This email contains confidential or legally privileged information and is for the sole use of its intended recipient. Any unauthorized review, use, copying or forwarding of this email or the content of this email is strictly prohibited.

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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

[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
>  
>  
>  
> 
>  
>  
>  
> 
> 
> 
> 
>