src/os/windows/vm/os_windows.cpp

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.

@@ -714,10 +714,20 @@
 #if _MSC_VER < 1300
 typedef UINT_PTR DWORD_PTR;
 #endif
 
 int os::active_processor_count() {
+  // User has overridden the number of active processors
+  if (ActiveProcessorCount > 0) {
+    if (PrintActiveCpus) {
+      tty->print_cr("active_processor_count: "
+                    "active processor count set by user : %d",
+                     ActiveProcessorCount);
+    }
+    return ActiveProcessorCount;
+  }
+
   DWORD_PTR lpProcessAffinityMask = 0;
   DWORD_PTR lpSystemAffinityMask = 0;
   int proc_count = processor_count();
   if (proc_count <= sizeof(UINT_PTR) * BitsPerByte &&
       GetProcessAffinityMask(GetCurrentProcess(), &lpProcessAffinityMask, &lpSystemAffinityMask)) {