Cache VPO state on for performance.

RTC: 43789
Change-Id: I80da1db355ac4ad838c36575ad183a0002569cd4
Reviewed-on: http://gfw160.austin.ibm.com:8080/gerrit/1574
Tested-by: Jenkins Server
Reviewed-by: A. Patrick Williams III <iawillia@us.ibm.com>

1 files changed, 51 insertions, 34 deletions

diff --git a/src/usr/targeting/common/util.C b/src/usr/targeting/common/util.C
index ce85567aa..d3ca08e28 100644
--- a/src/usr/targeting/common/util.C
+++ b/src/usr/targeting/common/util.C
@@ -1,26 +1,26 @@
-//  IBM_PROLOG_BEGIN_TAG
-//  This is an automatically generated prolog.
-//
-//  $Source: src/usr/targeting/util.C $
-//
-//  IBM CONFIDENTIAL
-//
-//  COPYRIGHT International Business Machines Corp. 2012
-//
-//  p1
-//
-//  Object Code Only (OCO) source materials
-//  Licensed Internal Code Source Materials
-//  IBM HostBoot Licensed Internal Code
-//
-//  The source code for this program is not published or other-
-//  wise divested of its trade secrets, irrespective of what has
-//  been deposited with the U.S. Copyright Office.
-//
-//  Origin: 30
-//
-//  IBM_PROLOG_END
-
+/*  IBM_PROLOG_BEGIN_TAG
+ *  This is an automatically generated prolog.
+ *
+ *  $Source: src/usr/targeting/common/util.C $
+ *
+ *  IBM CONFIDENTIAL
+ *
+ *  COPYRIGHT International Business Machines Corp. 2012
+ *
+ *  p1
+ *
+ *  Object Code Only (OCO) source materials
+ *  Licensed Internal Code Source Materials
+ *  IBM HostBoot Licensed Internal Code
+ *
+ *  The source code for this program is not published or other-
+ *  wise divested of its trade secrets, irrespective of what has
+ *  been deposited with the U.S. Copyright Office.
+ *
+ *  Origin: 30
+ *
+ *  IBM_PROLOG_END_TAG
+ */
 /**
  *  @file targeting/common/util.C
  *
@@ -43,18 +43,35 @@ namespace TARGETING
  */
 bool is_vpo( void )
 {
-    Target * sys = NULL;
-    targetService().getTopLevelTarget( sys );
-    uint8_t vpo_mode = 0;
-    if( unlikely( //compiler hint to optimize the false path
-        sys
-        && sys->tryGetAttr<ATTR_IS_SIMULATION>(vpo_mode)
-        && (vpo_mode == 1)
-        ) )
+    struct IsVpoFunctor
     {
-       return true;
-    }
-    return false;
+        static bool operate()
+        {
+            bool rc = false;
+
+            Target* sys = NULL;
+            targetService().getTopLevelTarget(sys);
+
+            uint8_t vpo_mode = 0;
+            if (unlikely(sys &&
+                         sys->tryGetAttr<ATTR_IS_SIMULATION>(vpo_mode) &&
+                         (1 == vpo_mode)))
+            {
+                rc = true;
+            }
+            return rc;
+        }
+    };
+
+#ifdef __HOSTBOOT_MODULE
+    // In Hostboot this value cannot change, so cache it as a static.
+    static bool is_vpo_mode = IsVpoFunctor::operate();
+    return is_vpo_mode;
+#else
+    // On FSP, assumption is that the user could change this, so we cannot
+    // cache it as a static.  Read from the attribute directly.
+    return IsVpoFunctor::operate();
+#endif
 };
 
 /**