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* [Patch v2 0/6] Fix performance issue caused by Set MSR task.
@ 2018-10-17  2:16 Eric Dong
  2018-10-17  2:16 ` [Patch v2 1/6] UefiCpuPkg/Include/AcpiCpuData.h: Add Semaphore related Information Eric Dong
                   ` (7 more replies)
  0 siblings, 8 replies; 18+ messages in thread
From: Eric Dong @ 2018-10-17  2:16 UTC (permalink / raw)
  To: edk2-devel; +Cc: Ruiyu Ni, Laszlo Ersek

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



^ permalink raw reply	[flat|nested] 18+ messages in thread

end of thread, other threads:[~2018-10-18  7:37 UTC | newest]

Thread overview: 18+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2018-10-17  2:16 [Patch v2 0/6] Fix performance issue caused by Set MSR task Eric Dong
2018-10-17  2:16 ` [Patch v2 1/6] UefiCpuPkg/Include/AcpiCpuData.h: Add Semaphore related Information Eric Dong
2018-10-18  3:04   ` Ni, Ruiyu
2018-10-18  3:10   ` Ni, Ruiyu
2018-10-17  2:16 ` [Patch v2 2/6] UefiCpuPkg/RegisterCpuFeaturesLib.h: Add new dependence types Eric Dong
2018-10-18  3:31   ` Ni, Ruiyu
2018-10-17  2:16 ` [Patch v2 3/6] UefiCpuPkg/RegisterCpuFeaturesLib: Add logic to support semaphore type Eric Dong
2018-10-18  5:46   ` Ni, Ruiyu
2018-10-17  2:16 ` [Patch v2 4/6] UefiCpuPkg/PiSmmCpuDxeSmm: " Eric Dong
2018-10-18  5:54   ` Ni, Ruiyu
2018-10-17  2:16 ` [Patch v2 5/6] UefiCpuPkg/CpuS3DataDxe: Keep old data if value already existed Eric Dong
2018-10-18  5:57   ` Ni, Ruiyu
2018-10-17  2:16 ` [Patch v2 6/6] UefiCpuPkg/CpuCommonFeaturesLib: Register MSR base on scope Info Eric Dong
2018-10-18  6:01   ` Ni, Ruiyu
2018-10-17 17:33 ` [Patch v2 0/6] Fix performance issue caused by Set MSR task Laszlo Ersek
2018-10-18  7:36   ` Dong, Eric
2018-10-18  2:12 ` Ni, Ruiyu
2018-10-18  2:35   ` Dong, Eric

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