Re: [edk2-devel] [PATCH v2] UefiCpuPkg/MpInitLib DXE: Add PCD to control AP status check interval

["Wu, Hao A" <hao.a.wu@intel.com>]

> -----Original Message-----
> From: Zeng, Star
> Sent: Tuesday, March 24, 2020 3:02 PM
> To: devel@edk2.groups.io; Wu, Hao A
> Cc: Dong, Eric; Ni, Ray; Laszlo Ersek; Kinney, Michael D; Brian J . Johnson; Zeng,
> Star
> Subject: RE: [edk2-devel] [PATCH v2] UefiCpuPkg/MpInitLib DXE: Add PCD to
> control AP status check interval
> 
> The code logic is good to me.
> Only minor concern, do we really need the PCD to be UINT64 type? :)


Hi Star,

I am thinking the UINT64 type fits with the parameter for the SetTimer()
service in EFI_BOOT_SERVICES when preparing the patch.

If there is concern, I can switch it to other type.

Best Regards,
Hao Wu


> 
> Thanks,
> Star
> 
> > -----Original Message-----
> > From: devel@edk2.groups.io [mailto:devel@edk2.groups.io] On Behalf Of
> > Wu, Hao A
> > Sent: Tuesday, March 24, 2020 2:33 PM
> > To: devel@edk2.groups.io
> > Cc: Wu, Hao A <hao.a.wu@intel.com>; Dong, Eric <eric.dong@intel.com>; Ni,
> > Ray <ray.ni@intel.com>; Laszlo Ersek <lersek@redhat.com>; Kinney, Michael
> > D <michael.d.kinney@intel.com>; Zeng, Star <star.zeng@intel.com>; Brian J .
> > Johnson <brian.johnson@hpe.com>
> > Subject: [edk2-devel] [PATCH v2] UefiCpuPkg/MpInitLib DXE: Add PCD to
> > control AP status check interval
> >
> > REF:https://bugzilla.tianocore.org/show_bug.cgi?id=2627
> >
> > The commit will introduce a static PCD to specify the periodic interval for
> > checking the AP status when MP services StartupAllAPs() and
> > StartupThisAP() are being executed in a non-blocking manner. Or in other
> > words, specifies the interval for callback function CheckApsStatus().
> >
> > The purpose is to provide the platform owners with the ability to choose the
> > proper interval value to trigger CheckApsStatus() according to:
> > A) The number of processors in the system;
> > B) How MP services (StartupAllAPs & StartupThisAP) being used.
> >
> > Setting the PCD to a small value means the AP status check callback will be
> > trigerred more frequently, it can benefit the performance for the case when
> > the BSP uses WaitForEvent() or uses CheckEvent() in a loop to wait for AP(s)
> > to complete the task, especially when the task can be finished considerably
> > fast on AP(s).
> >
> > An example is within function CpuFeaturesInitialize() under
> > UefiCpuPkg/Library/RegisterCpuFeaturesLib/DxeRegisterCpuFeaturesLib.c,
> > where BSP will perform the same task with APs and requires all the
> > processors to finish the task before BSP proceeds to its next task.
> >
> > Setting the PCD to a big value, on the other hand, can reduce the impact on
> > BSP by the time being consumed in CheckApsStatus(), especially when the
> > number of processors is huge so that the time consumed in CheckApsStatus()
> > is not negligible.
> >
> > For least impact, the default value of the new PCD will be the same with the
> > current interval value, which is 100 milliseconds.
> >
> > Unitest done:
> > OS boot successfully.
> >
> > Cc: Eric Dong <eric.dong@intel.com>
> > Cc: Ray Ni <ray.ni@intel.com>
> > Cc: Laszlo Ersek <lersek@redhat.com>
> > Cc: Michael D Kinney <michael.d.kinney@intel.com>
> > Cc: Star Zeng <star.zeng@intel.com>
> > Cc: Brian J. Johnson <brian.johnson@hpe.com>
> > Signed-off-by: Hao A Wu <hao.a.wu@intel.com>
> > ---
> >  UefiCpuPkg/UefiCpuPkg.dec                     | 6 ++++++
> >  UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf | 2 +-
> >  UefiCpuPkg/Library/MpInitLib/DxeMpLib.c       | 3 +--
> >  UefiCpuPkg/UefiCpuPkg.uni                     | 5 ++++-
> >  4 files changed, 12 insertions(+), 4 deletions(-)
> >
> > diff --git a/UefiCpuPkg/UefiCpuPkg.dec b/UefiCpuPkg/UefiCpuPkg.dec index
> > e91dc68cbe..06a3d52060 100644
> > --- a/UefiCpuPkg/UefiCpuPkg.dec
> > +++ b/UefiCpuPkg/UefiCpuPkg.dec
> > @@ -230,6 +230,12 @@ [PcdsFixedAtBuild, PcdsPatchableInModule]
> >    # @Prompt This PCD is the nominal frequency of the core crystal clock in Hz
> > as is CPUID Leaf 0x15:ECX
> >
> > gUefiCpuPkgTokenSpaceGuid.PcdCpuCoreCrystalClockFrequency|24000000|
> > UINT64|0x32132113
> >
> > +  ## Specifies the periodic interval value in milliseconds for the
> > + status check  #  of APs for StartupAllAPs() and StartupThisAP()
> > + executed in non-blocking  #  mode in DXE phase.
> > +  # @Prompt Periodic interval value in milliseconds for AP status check in
> > DXE.
> > +
> > +
> > gUefiCpuPkgTokenSpaceGuid.PcdCpuApStatusCheckInterval|100|UINT64|0x
> > 000
> > + 0001E
> > +
> >  [PcdsFixedAtBuild, PcdsPatchableInModule, PcdsDynamic, PcdsDynamicEx]
> >    ## Specifies max supported number of Logical Processors.
> >    # @Prompt Configure max supported number of Logical Processors diff --git
> > a/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
> > b/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
> > index 45aaa179ff..05e004dc3c 100644
> > --- a/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
> > +++ b/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
> > @@ -69,5 +69,5 @@ [Pcd]
> >    gUefiCpuPkgTokenSpaceGuid.PcdCpuMicrocodePatchRegionSize         ##
> > CONSUMES
> >    gUefiCpuPkgTokenSpaceGuid.PcdCpuApLoopMode                       ##
> > CONSUMES
> >    gUefiCpuPkgTokenSpaceGuid.PcdCpuApTargetCstate                   ##
> > SOMETIMES_CONSUMES
> > +  gUefiCpuPkgTokenSpaceGuid.PcdCpuApStatusCheckInterval            ##
> > CONSUMES
> >    gEfiMdeModulePkgTokenSpaceGuid.PcdCpuStackGuard                  ##
> > CONSUMES
> > -
> > diff --git a/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
> > b/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
> > index a987c32109..683547dc99 100644
> > --- a/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
> > +++ b/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
> > @@ -15,7 +15,6 @@
> >
> >  #include <Protocol/Timer.h>
> >
> > -#define  AP_CHECK_INTERVAL     (EFI_TIMER_PERIOD_MILLISECONDS (100))
> >  #define  AP_SAFE_STACK_SIZE    128
> >
> >  CPU_MP_DATA      *mCpuMpData = NULL;
> > @@ -451,7 +450,7 @@ InitMpGlobalData (
> >    Status = gBS->SetTimer (
> >                    mCheckAllApsEvent,
> >                    TimerPeriodic,
> > -                  AP_CHECK_INTERVAL
> > +                  PcdGet64 (PcdCpuApStatusCheckInterval)
> >                    );
> >    ASSERT_EFI_ERROR (Status);
> >
> > diff --git a/UefiCpuPkg/UefiCpuPkg.uni b/UefiCpuPkg/UefiCpuPkg.uni index
> > c0d6ed5136..08d9b45f76 100644
> > --- a/UefiCpuPkg/UefiCpuPkg.uni
> > +++ b/UefiCpuPkg/UefiCpuPkg.uni
> > @@ -3,7 +3,7 @@
> >  //
> >  // This Package provides UEFI compatible CPU modules and libraries.
> >  //
> > -// Copyright (c) 2007 - 2015, Intel Corporation. All rights reserved.<BR>
> > +// Copyright (c) 2007 - 2020, Intel Corporation. All rights
> > +reserved.<BR>
> >  //
> >  // SPDX-License-Identifier: BSD-2-Clause-Patent  // @@ -275,3 +275,6 @@
> > #string
> > STR_gUefiCpuPkgTokenSpaceGuid_PcdCpuSmmMpTokenCountPerChunk_PR
> > OMPT  #language en-US "Specify the count of pre allocated SMM MP tokens
> > per chunk.\n"
> >
> >  #string
> > STR_gUefiCpuPkgTokenSpaceGuid_PcdCpuSmmMpTokenCountPerChunk_HE
> > LP    #language en-US "This value used to specify the count of pre allocated
> > SMM MP tokens per chunk.\n"
> > +
> > +#string
> > STR_gUefiCpuPkgTokenSpaceGuid_PcdCpuApStatusCheckInterval_PROMPT
> > #language en-US "Periodic interval value in milliseconds for AP status check in
> > DXE.\n"
> > +#string
> > STR_gUefiCpuPkgTokenSpaceGuid_PcdCpuApStatusCheckInterval_HELP
> > #language en-US "Periodic interval value in milliseconds for the status check
> > of APs for StartupAllAPs() and StartupThisAP() executed in non-blocking
> > mode in DXE phase.\n"
> > --
> > 2.12.0.windows.1
> >
> >
> >