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

["Zeng, Star" <star.zeng@intel.com>]

> -----Original Message-----
> From: Wu, Hao A
> Sent: Tuesday, March 24, 2020 3:12 PM
> To: Zeng, Star <star.zeng@intel.com>; devel@edk2.groups.io
> Cc: 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>; Brian J . Johnson <brian.johnson@hpe.com>
> Subject: RE: [edk2-devel] [PATCH v2] UefiCpuPkg/MpInitLib DXE: Add PCD to
> control AP status check interval
> 
> > -----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.

Got your good point.
For me, UINT32 (FFFFFFFFh = 4294967295d = 4294967.295 second = 71582.78825 minutes ~= 1193.0464708333333333333333333333 hours) should be totally enough.
I do not insist on that if others think UINT64 is ok.

Thanks,
Star

> 
> 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
> > >
> > >
> > >