From e52838d358d5062c4b1ed8e87bdc3d0f527095d3 Mon Sep 17 00:00:00 2001
From: Eric Dong <eric.dong@intel.com>
Date: Wed, 4 Jul 2018 16:29:07 +0800
Subject: [PATCH] UefiCpuPkg/MpInitLib: Optimize get processor number
 performance.

Current function has low performance because it calls GetApicId
in the loop, so it maybe called more than once.

New logic call GetApicId once and base on this value to search
the processor.

Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Jeff Fan <vanjeff_919@hotmail.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Eric Dong <eric.dong@intel.com>
Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
---
 UefiCpuPkg/Library/MpInitLib/MpLib.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.c b/UefiCpuPkg/Library/MpInitLib/MpLib.c
index e5c701ddeb..c82b985943 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.c
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.c
@@ -435,16 +435,19 @@ GetProcessorNumber (
   UINTN                   TotalProcessorNumber;
   UINTN                   Index;
   CPU_INFO_IN_HOB         *CpuInfoInHob;
+  UINT32                  CurrentApicId;
 
   CpuInfoInHob = (CPU_INFO_IN_HOB *) (UINTN) CpuMpData->CpuInfoInHob;
 
   TotalProcessorNumber = CpuMpData->CpuCount;
+  CurrentApicId = GetApicId ();
   for (Index = 0; Index < TotalProcessorNumber; Index ++) {
-    if (CpuInfoInHob[Index].ApicId == GetApicId ()) {
+    if (CpuInfoInHob[Index].ApicId == CurrentApicId) {
       *ProcessorNumber = Index;
       return EFI_SUCCESS;
     }
   }
+
   return EFI_NOT_FOUND;
 }
 
-- 
2.39.2