diff --git a/windows/syscall_windows.go b/windows/syscall_windows.go
index 200b62a..cf44e69 100644
--- a/windows/syscall_windows.go
+++ b/windows/syscall_windows.go
@@ -363,6 +363,8 @@
 //sys	SetProcessWorkingSetSizeEx(hProcess Handle, dwMinimumWorkingSetSize uintptr, dwMaximumWorkingSetSize uintptr, flags uint32) (err error)
 //sys	GetCommTimeouts(handle Handle, timeouts *CommTimeouts) (err error)
 //sys	SetCommTimeouts(handle Handle, timeouts *CommTimeouts) (err error)
+//sys	GetActiveProcessorCount(groupNumber uint16) (ret uint32)
+//sys	GetMaximumProcessorCount(groupNumber uint16) (ret uint32)
 
 // Volume Management Functions
 //sys	DefineDosDevice(flags uint32, deviceName *uint16, targetPath *uint16) (err error) = DefineDosDeviceW
diff --git a/windows/types_windows.go b/windows/types_windows.go
index bb31abd..e19471c 100644
--- a/windows/types_windows.go
+++ b/windows/types_windows.go
@@ -3172,3 +3172,5 @@
 	SizeOfImage uint32
 	EntryPoint  uintptr
 }
+
+const ALL_PROCESSOR_GROUPS = 0xFFFF
diff --git a/windows/zsyscall_windows.go b/windows/zsyscall_windows.go
index 1055d47..9ea1a44 100644
--- a/windows/zsyscall_windows.go
+++ b/windows/zsyscall_windows.go
@@ -226,6 +226,7 @@
 	procFreeLibrary                                          = modkernel32.NewProc("FreeLibrary")
 	procGenerateConsoleCtrlEvent                             = modkernel32.NewProc("GenerateConsoleCtrlEvent")
 	procGetACP                                               = modkernel32.NewProc("GetACP")
+	procGetActiveProcessorCount                              = modkernel32.NewProc("GetActiveProcessorCount")
 	procGetCommTimeouts                                      = modkernel32.NewProc("GetCommTimeouts")
 	procGetCommandLineW                                      = modkernel32.NewProc("GetCommandLineW")
 	procGetComputerNameExW                                   = modkernel32.NewProc("GetComputerNameExW")
@@ -251,6 +252,7 @@
 	procGetLogicalDriveStringsW                              = modkernel32.NewProc("GetLogicalDriveStringsW")
 	procGetLogicalDrives                                     = modkernel32.NewProc("GetLogicalDrives")
 	procGetLongPathNameW                                     = modkernel32.NewProc("GetLongPathNameW")
+	procGetMaximumProcessorCount                             = modkernel32.NewProc("GetMaximumProcessorCount")
 	procGetModuleFileNameW                                   = modkernel32.NewProc("GetModuleFileNameW")
 	procGetModuleHandleExW                                   = modkernel32.NewProc("GetModuleHandleExW")
 	procGetNamedPipeHandleStateW                             = modkernel32.NewProc("GetNamedPipeHandleStateW")
@@ -1967,6 +1969,12 @@
 	return
 }
 
+func GetActiveProcessorCount(groupNumber uint16) (ret uint32) {
+	r0, _, _ := syscall.Syscall(procGetActiveProcessorCount.Addr(), 1, uintptr(groupNumber), 0, 0)
+	ret = uint32(r0)
+	return
+}
+
 func GetCommTimeouts(handle Handle, timeouts *CommTimeouts) (err error) {
 	r1, _, e1 := syscall.Syscall(procGetCommTimeouts.Addr(), 2, uintptr(handle), uintptr(unsafe.Pointer(timeouts)), 0)
 	if r1 == 0 {
@@ -2169,6 +2177,12 @@
 	return
 }
 
+func GetMaximumProcessorCount(groupNumber uint16) (ret uint32) {
+	r0, _, _ := syscall.Syscall(procGetMaximumProcessorCount.Addr(), 1, uintptr(groupNumber), 0, 0)
+	ret = uint32(r0)
+	return
+}
+
 func GetModuleFileName(module Handle, filename *uint16, size uint32) (n uint32, err error) {
 	r0, _, e1 := syscall.Syscall(procGetModuleFileNameW.Addr(), 3, uintptr(module), uintptr(unsafe.Pointer(filename)), uintptr(size))
 	n = uint32(r0)