UefiCpuPkg/MpInitLib: Do not wakeup AP if only one processor supported

If MaxLogicalProcessorNumber is only 1, we needn't to wake up APs at all
and needn't to register callback functions.

It could improve boot performance on single supported system.

https://bugzilla.tianocore.org/show_bug.cgi?id=204

Cc: Feng Tian <feng.tian@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>

diff --git a/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c b/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
index b399f1c24d301158ee79c8245a38ba818c1b6b05..eb36d6f78d972716408378517cc9b8c35e4b089c 100644 (file)
--- a/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
+++ b/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
@@ -290,6 +290,13 @@ InitMpGlobalData (
 \r
   SaveCpuMpData (CpuMpData);\r
 \r
+  if (CpuMpData->CpuCount == 1) {\r
+    //\r
+    // If only BSP exists, return\r
+    //\r
+    return;\r
+  }\r
+\r
   //\r
   // Avoid APs access invalid buff data which allocated by BootServices,\r
   // so we will allocate reserved data for AP loop code.\r

diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.c b/UefiCpuPkg/Library/MpInitLib/MpLib.c
index 56b870e52748b42672b086666f73880df7f8af2d..a0edc55f5254b0031cc6ecf97a8bbd4414f66128 100644 (file)
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.c
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.c
@@ -1143,6 +1143,7 @@ MpInitLibInitialize (
   } else {\r
     MaxLogicalProcessorNumber = OldCpuMpData->CpuCount;\r
   }\r
+  ASSERT (MaxLogicalProcessorNumber != 0);\r
 \r
   AsmGetAddressMap (&AddressMap);\r
   ApResetVectorSize = AddressMap.RendezvousFunnelSize + sizeof (MP_CPU_EXCHANGE_INFO);\r
@@ -1209,10 +1210,12 @@ MpInitLibInitialize (
   MtrrGetAllMtrrs (&CpuMpData->MtrrTable);\r
 \r
   if (OldCpuMpData == NULL) {\r
-    //\r
-    // Wakeup all APs and calculate the processor count in system\r
-    //\r
-    CollectProcessorCount (CpuMpData);\r
+    if (MaxLogicalProcessorNumber > 1) {\r
+      //\r
+      // Wakeup all APs and calculate the processor count in system\r
+      //\r
+      CollectProcessorCount (CpuMpData);\r
+    }\r
   } else {\r
     //\r
     // APs have been wakeup before, just get the CPU Information\r
@@ -1238,19 +1241,21 @@ MpInitLibInitialize (
         sizeof (CPU_VOLATILE_REGISTERS)\r
         );\r
     }\r
-    //\r
-    // Wakeup APs to do some AP initialize sync\r
-    //\r
-    WakeUpAP (CpuMpData, TRUE, 0, ApInitializeSync, CpuMpData);\r
-    //\r
-    // Wait for all APs finished initialization\r
-    //\r
-    while (CpuMpData->FinishedCount < (CpuMpData->CpuCount - 1)) {\r
-      CpuPause ();\r
-    }\r
-    CpuMpData->InitFlag = ApInitDone;\r
-    for (Index = 0; Index < CpuMpData->CpuCount; Index++) {\r
-      SetApState (&CpuMpData->CpuData[Index], CpuStateIdle);\r
+    if (MaxLogicalProcessorNumber > 1) {\r
+      //\r
+      // Wakeup APs to do some AP initialize sync\r
+      //\r
+      WakeUpAP (CpuMpData, TRUE, 0, ApInitializeSync, CpuMpData);\r
+      //\r
+      // Wait for all APs finished initialization\r
+      //\r
+      while (CpuMpData->FinishedCount < (CpuMpData->CpuCount - 1)) {\r
+        CpuPause ();\r
+      }\r
+      CpuMpData->InitFlag = ApInitDone;\r
+      for (Index = 0; Index < CpuMpData->CpuCount; Index++) {\r
+        SetApState (&CpuMpData->CpuData[Index], CpuStateIdle);\r
+      }\r
     }\r
   }\r
 \r

diff --git a/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c b/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c
index e242d37b3b3973ca78724c5d2c485191d74b8350..1f2fcb8b1ceaa0ed1ac2c15b75fe85636a042c29 100644 (file)
--- a/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c
+++ b/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c
@@ -321,6 +321,14 @@ InitMpGlobalData (
   EFI_STATUS      Status;\r
 \r
   SaveCpuMpData (CpuMpData);\r
+\r
+  if (CpuMpData->CpuCount == 1) {\r
+    //\r
+    // If only BSP exists, return\r
+    //\r
+    return;\r
+  }\r
+\r
   //\r
   // Register an event for EndOfPei\r
   //\r