" 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