[Jikesrvm-commits] SF.net SVN: jikesrvm: [13396] rvmroot/trunk/MMTk/src/org/mmtk/plan/ generational

[<dfr...@us...>]

Revision: 13396
          http://jikesrvm.svn.sourceforge.net/jikesrvm/?rev=13396&view=rev
Author:   dframpton-oss
Date:     2007-08-29 02:42:09 -0700 (Wed, 29 Aug 2007)

Log Message:
-----------
Add an option to allow using the generational collector in combination with the static write barrier instead of scanning the statics every nursery gc. This is primarily intended as a tool for ensuring static write barriers do not regress, but it may be interesting to compare the performance between the two modes.

Modified Paths:
--------------
    rvmroot/trunk/MMTk/src/org/mmtk/plan/generational/Gen.java
    rvmroot/trunk/MMTk/src/org/mmtk/plan/generational/GenCollector.java
    rvmroot/trunk/MMTk/src/org/mmtk/plan/generational/GenConstraints.java

Modified: rvmroot/trunk/MMTk/src/org/mmtk/plan/generational/Gen.java
===================================================================
--- rvmroot/trunk/MMTk/src/org/mmtk/plan/generational/Gen.java	2007-08-29 09:03:39 UTC (rev 13395)
+++ rvmroot/trunk/MMTk/src/org/mmtk/plan/generational/Gen.java	2007-08-29 09:42:09 UTC (rev 13396)
@@ -50,6 +50,7 @@
   protected static final float SURVIVAL_ESTIMATE = (float) 0.8; // est yield
   protected static final float MATURE_FRACTION = (float) 0.5; // est yield
   public static final boolean IGNORE_REMSETS = false;
+  public static final boolean USE_STATIC_WRITE_BARRIER = false;
 
   // Allocators
   public static final int ALLOC_NURSERY        = ALLOC_DEFAULT;

Modified: rvmroot/trunk/MMTk/src/org/mmtk/plan/generational/GenCollector.java
===================================================================
--- rvmroot/trunk/MMTk/src/org/mmtk/plan/generational/GenCollector.java	2007-08-29 09:03:39 UTC (rev 13395)
+++ rvmroot/trunk/MMTk/src/org/mmtk/plan/generational/GenCollector.java	2007-08-29 09:42:09 UTC (rev 13396)
@@ -90,6 +90,14 @@
       return;
     }
 
+    if (phaseId == StopTheWorld.ROOTS) {
+      if (!Gen.USE_STATIC_WRITE_BARRIER || global().traceFullHeap()) {
+        VM.scanning.computeStaticRoots(getCurrentTrace());
+      }
+      VM.scanning.computeThreadRoots(getCurrentTrace());
+      return;
+    }
+
     if (phaseId == Gen.BOOTIMAGE_ROOTS) {
       if (global().traceFullHeap()) {
         super.collectionPhase(phaseId, primary);

Modified: rvmroot/trunk/MMTk/src/org/mmtk/plan/generational/GenConstraints.java
===================================================================
--- rvmroot/trunk/MMTk/src/org/mmtk/plan/generational/GenConstraints.java	2007-08-29 09:03:39 UTC (rev 13395)
+++ rvmroot/trunk/MMTk/src/org/mmtk/plan/generational/GenConstraints.java	2007-08-29 09:42:09 UTC (rev 13396)
@@ -40,4 +40,7 @@
 
   /** @return True if this plan requires a write barrier */
   public boolean needsWriteBarrier() { return true; }
+
+  /** @return True if this plan requires a static barrier */
+  public boolean needsStaticWriteBarrier() { return Gen.USE_STATIC_WRITE_BARRIER; }
 }


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