Re: [Patch v2 0/6] Fix performance issue caused by Set MSR task.

["Ni, Ruiyu" <ruiyu.ni@intel.com>]

Eric,
Can you post your changes to github yours mirror repo?
I found #3/6 cannot be applied to my code properly.

Thanks/Ray

> -----Original Message-----
> From: Dong, Eric
> Sent: Wednesday, October 17, 2018 10:16 AM
> To: edk2-devel@lists.01.org
> Cc: Ni, Ruiyu <ruiyu.ni@intel.com>; Laszlo Ersek <lersek@redhat.com>
> Subject: [Patch v2 0/6] Fix performance issue caused by Set MSR task.
> 
> V2 changes include:
> 1. Include the change for CpuCommonFeaturesLib which used to set MSR
> base on its scope info.
> 2. Include the change for CpuS3DataDxe driver which also handle the
> AcpiCpuData data.
> 3. Update code base on feedback for V1 changes.
> 
> V1 changes include:
> In a system which has multiple cores, current set register value task costs
> huge times.
> After investigation, current set MSR task costs most of the times. Current
> logic uses SpinLock to let set MSR task as an single thread task for all cores.
> Because MSR has scope attribute which may cause GP fault if multiple APs
> set MSR at the same time, current logic use an easiest solution (use SpinLock)
> to avoid this issue, but it will cost huge times.
> 
> In order to fix this performance issue, new solution will set MSRs base on
> their scope attribute. After this, the SpinLock will not needed. Without
> SpinLock, new issue raised which is caused by MSR dependence. For
> example, MSR A depends on MSR B which means MSR A must been set after
> MSR B has been set. Also MSR B is package scope level and MSR A is thread
> scope level. If system has multiple threads, Thread 1 needs to set the thread
> level MSRs and thread 2 needs to set thread and package level MSRs. Set
> MSRs task for thread 1 and thread 2 like below:
> 
>             Thread 1                 Thread 2
> MSR B          N                        Y
> MSR A          Y                        Y
> 
> If driver don't control execute MSR order, for thread 1, it will execute MSR A
> first, but at this time, MSR B not been executed yet by thread 2. system may
> trig exception at this time.
> 
> In order to fix the above issue, driver introduces semaphore logic to control
> the MSR execute sequence. For the above case, a semaphore will be add
> between MSR A and B for all threads. Semaphore has scope info for it. The
> possible scope value is core or package.
> For each thread, when it meets a semaphore during it set registers, it will 1)
> release semaphore (+1) for each threads in this core or package(based on
> the scope info for this
> semaphore) 2) acquire semaphore (-1) for all the threads in this core or
> package(based on the scope info for this semaphore). With these two steps,
> driver can control MSR sequence. Sample code logic like below:
> 
>   //
>   // First increase semaphore count by 1 for processors in this package.
>   //
>   for (ProcessorIndex = 0; ProcessorIndex < PackageThreadsCount ;
> ProcessorIndex ++) {
>     LibReleaseSemaphore ((UINT32 *) &SemaphorePtr[PackageOffset +
> ProcessorIndex]);
>   }
>   //
>   // Second, check whether the count has reach the check number.
>   //
>   for (ProcessorIndex = 0; ProcessorIndex < ValidApCount; ProcessorIndex ++)
> {
>     LibWaitForSemaphore (&SemaphorePtr[ApOffset]);
>   }
> 
> Platform Requirement:
> 1. This change requires register MSR setting base on MSR scope info. If still
> register MSR
>    for all threads, exception may raised.
> 
> Known limitation:
> 1. Current CpuFeatures driver supports DXE instance and PEI instance. But
> semaphore logic
>    requires Aps execute in async mode which is not supported by PEI driver.
> So CpuFeature
>    PEI instance not works after this change. We plan to support async mode
> for PEI in phase
>    2 for this task.
> 2. Current execute MSR task code in duplicated in PiSmmCpuDxeSmm driver
> and
>    RegisterCpuFeaturesLib library because the schedule limitation. Will merge
> the code to
>    RegisterCpuFeaturesLib and export as an API in phase 2 for this task.
> 
> Cc: Ruiyu Ni <ruiyu.ni@intel.com>
> Cc: Laszlo Ersek <lersek@redhat.com>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Eric Dong <eric.dong@intel.com>
> 
> 
> Eric Dong (6):
>   UefiCpuPkg/Include/AcpiCpuData.h: Add Semaphore related Information.
>   UefiCpuPkg/RegisterCpuFeaturesLib.h: Add new dependence types.
>   UefiCpuPkg/RegisterCpuFeaturesLib: Add logic to support semaphore
>     type.
>   UefiCpuPkg/PiSmmCpuDxeSmm: Add logic to support semaphore type.
>   UefiCpuPkg/CpuS3DataDxe: Keep old data if value already existed.
>   UefiCpuPkg/CpuCommonFeaturesLib: Register MSR base on scope Info.
> 
>  UefiCpuPkg/CpuS3DataDxe/CpuS3Data.c                |   2 +
>  UefiCpuPkg/Include/AcpiCpuData.h                   |  45 +-
>  .../Include/Library/RegisterCpuFeaturesLib.h       |  25 +-
>  UefiCpuPkg/Library/CpuCommonFeaturesLib/C1e.c      |   8 +
>  UefiCpuPkg/Library/CpuCommonFeaturesLib/Eist.c     |  12 +
>  .../Library/CpuCommonFeaturesLib/ExecuteDisable.c  |  10 +
>  .../Library/CpuCommonFeaturesLib/FastStrings.c     |  12 +
>  .../Library/CpuCommonFeaturesLib/FeatureControl.c  |  38 ++
>  .../CpuCommonFeaturesLib/LimitCpuIdMaxval.c        |  14 +
>  .../Library/CpuCommonFeaturesLib/MachineCheck.c    |  38 ++
>  .../Library/CpuCommonFeaturesLib/MonitorMwait.c    |  15 +
>  .../Library/CpuCommonFeaturesLib/PendingBreak.c    |  11 +
>  UefiCpuPkg/Library/CpuCommonFeaturesLib/Ppin.c     |  11 +
>  .../Library/CpuCommonFeaturesLib/ProcTrace.c       |  11 +
>  UefiCpuPkg/Library/CpuCommonFeaturesLib/X2Apic.c   |  10 +
>  .../RegisterCpuFeaturesLib/CpuFeaturesInitialize.c | 438
> ++++++++++++++++---
>  .../DxeRegisterCpuFeaturesLib.c                    |  71 ++-
>  .../DxeRegisterCpuFeaturesLib.inf                  |   3 +
>  .../PeiRegisterCpuFeaturesLib.c                    |  55 ++-
>  .../PeiRegisterCpuFeaturesLib.inf                  |   1 +
>  .../RegisterCpuFeaturesLib/RegisterCpuFeatures.h   |  61 ++-
>  .../RegisterCpuFeaturesLib.c                       | 484 ++++++++++++++++++---
>  UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c                  | 406 +++++++++++------
>  UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c              |   3 -
>  UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h         |   3 +-
>  25 files changed, 1505 insertions(+), 282 deletions(-)
> 
> --
> 2.15.0.windows.1