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changeset 23043:c00fc84509da

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restructured monitorenter snippet for one test fewer on fast path and added marker node for that path
author Doug Simon <doug.simon@oracle.com>
date Fri, 20 Nov 2015 06:42:41 +0100
parents cbe35e56ae82
children 17e704e362b5
files graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/nodes/FastAcquireBiasedLockNode.java graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/replacements/MonitorSnippets.java
diffstat 2 files changed, 76 insertions(+), 17 deletions(-) [+]
line wrap: on
line diff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/nodes/FastAcquireBiasedLockNode.java	Fri Nov 20 06:42:41 2015 +0100
@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2015, 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.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package com.oracle.graal.hotspot.nodes;
+
+import com.oracle.graal.compiler.common.type.StampFactory;
+import com.oracle.graal.graph.NodeClass;
+import com.oracle.graal.nodeinfo.NodeInfo;
+import com.oracle.graal.nodes.FixedWithNextNode;
+import com.oracle.graal.nodes.ValueNode;
+import com.oracle.graal.nodes.spi.LIRLowerable;
+import com.oracle.graal.nodes.spi.NodeLIRBuilderTool;
+
+/**
+ * Marks the control flow path where an object acquired a biased lock because the lock was already
+ * biased to the object on the current thread.
+ */
+@NodeInfo
+public final class FastAcquireBiasedLockNode extends FixedWithNextNode implements LIRLowerable {
+    public static final NodeClass<FastAcquireBiasedLockNode> TYPE = NodeClass.create(FastAcquireBiasedLockNode.class);
+
+    @Input ValueNode object;
+
+    public FastAcquireBiasedLockNode(ValueNode object) {
+        super(TYPE, StampFactory.forVoid());
+        this.object = object;
+    }
+
+    public ValueNode object() {
+        return object;
+    }
+
+    public void generate(NodeLIRBuilderTool generator) {
+        // This is just a marker node so it generates nothing
+    }
+
+    @NodeIntrinsic
+    public static native void mark(Object object);
+}
--- a/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/replacements/MonitorSnippets.java	Fri Nov 20 03:08:32 2015 +0100
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/replacements/MonitorSnippets.java	Fri Nov 20 06:42:41 2015 +0100
@@ -77,6 +77,7 @@
 import com.oracle.graal.hotspot.meta.HotSpotRegistersProvider;
 import com.oracle.graal.hotspot.nodes.CurrentLockNode;
 import com.oracle.graal.hotspot.nodes.DirectCompareAndSwapNode;
+import com.oracle.graal.hotspot.nodes.FastAcquireBiasedLockNode;
 import com.oracle.graal.hotspot.nodes.MonitorCounterNode;
 import com.oracle.graal.hotspot.word.KlassPointer;
 import com.oracle.graal.nodes.BreakpointNode;
@@ -241,26 +242,27 @@
             // pointers to allow age to be placed into low bits.
             final Word biasableLockBits = mark.and(biasedLockMaskInPlace());
 
-            // First check to see whether biasing is enabled for this object
+            // Check whether the bias pattern is present in the object's mark word
+            // and the bias owner and the epoch are both still current.
+            final Word prototypeMarkWord = hub.readWord(prototypeMarkWordOffset(), PROTOTYPE_MARK_WORD_LOCATION);
+            final Word thread = registerAsWord(threadRegister);
+            final Word tmp = prototypeMarkWord.or(thread).xor(mark).and(~ageMaskInPlace());
+            trace(trace, "prototypeMarkWord: 0x%016lx\n", prototypeMarkWord);
+            trace(trace, "           thread: 0x%016lx\n", thread);
+            trace(trace, "              tmp: 0x%016lx\n", tmp);
+            if (probability(FREQUENT_PROBABILITY, tmp.equal(0))) {
+                // Object is already biased to current thread -> done
+                traceObject(trace, "+lock{bias:existing}", object, true);
+                lockBiasExisting.inc();
+                FastAcquireBiasedLockNode.mark(object);
+                return;
+            }
+
+            // Now check to see whether biasing is enabled for this object
             if (probability(NOT_FREQUENT_PROBABILITY, biasableLockBits.notEqual(Word.unsigned(biasedLockPattern())))) {
                 // Biasing not enabled -> fall through to lightweight locking
                 unbiasable.inc();
             } else {
-                // The bias pattern is present in the object's mark word. Need to check
-                // whether the bias owner and the epoch are both still current.
-                final Word prototypeMarkWord = hub.readWord(prototypeMarkWordOffset(), PROTOTYPE_MARK_WORD_LOCATION);
-                final Word thread = registerAsWord(threadRegister);
-                final Word tmp = prototypeMarkWord.or(thread).xor(mark).and(~ageMaskInPlace());
-                trace(trace, "prototypeMarkWord: 0x%016lx\n", prototypeMarkWord);
-                trace(trace, "           thread: 0x%016lx\n", thread);
-                trace(trace, "              tmp: 0x%016lx\n", tmp);
-                if (probability(FREQUENT_PROBABILITY, tmp.equal(0))) {
-                    // Object is already biased to current thread -> done
-                    traceObject(trace, "+lock{bias:existing}", object, true);
-                    lockBiasExisting.inc();
-                    return;
-                }
-
                 // At this point we know that the mark word has the bias pattern and
                 // that we are not the bias owner in the current epoch. We need to
                 // figure out more details about the state of the mark word in order to
@@ -695,5 +697,4 @@
     public static final SnippetCounter unlockCas = new SnippetCounter(unlockCounters, "unlock{cas}", "cas-unlocked an object");
     public static final SnippetCounter unlockCasRecursive = new SnippetCounter(unlockCounters, "unlock{cas:recursive}", "cas-unlocked an object, recursive");
     public static final SnippetCounter unlockStub = new SnippetCounter(unlockCounters, "unlock{stub}", "stub-unlocked an object");
-
 }