Fix bad performance in changing page attributes

[edk2] [PATCH 0/2] Fix bad performance in changing page attributes

Jian J Wang posted 2 patches 6 years, 11 months ago

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UefiCpuPkg/CpuDxe/CpuPageTable.c     | 85 +++---------------------------------
UefiCpuPkg/Library/MpInitLib/MpLib.c |  6 +++
2 files changed, 11 insertions(+), 80 deletions(-)

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[edk2] [PATCH 0/2] Fix bad performance in changing page attributes

Posted by Jian J Wang 6 years, 11 months ago

There's a great performance down if we enable heap guard features.
This feature will frequently update page attribute to set/unset guard
pages, which is done by CpuArchProtocol.SetMemoryAttributes. In the
implementation of this method (in CpuDxe), it will call
MpProtocol.StartupAllAps() to flush TLB for all APs after updating
page attributes. We found that StartupAllAps() will spend a lot of
time to complete the flush operation. For example, listing a folder
content in shell will take 55s to complete. Normally it should take
less than 5s.

The solution is removing the flush operation for AP in CpuDxe driver
but let AP do it in its own wakeup code. There's no need to flush TLB
for AP who has no chance to run code.

Jian J Wang (2):
  UefiCpuPkg/MpInitLib: force flushing TLB for AP in mwait loop mode
  UefiCpuPkg/CpuDxe: remove all code to flush TLB for APs

 UefiCpuPkg/CpuDxe/CpuPageTable.c     | 85 +++---------------------------------
 UefiCpuPkg/Library/MpInitLib/MpLib.c |  6 +++
 2 files changed, 11 insertions(+), 80 deletions(-)

-- 
2.15.1.windows.2

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