Imported WebKit commit 2ea9d364d0f6efa8fa64acf19f451504c59be0e4 (http://svn.webkit.org/repository/webkit/trunk@104285)

1 files changed, 69 insertions, 0 deletions

diff --git a/Source/JavaScriptCore/wtf/HashTable.cpp b/Source/JavaScriptCore/wtf/HashTable.cpp
new file mode 100644
index 000000000..71d3f86ce
--- /dev/null
+++ b/Source/JavaScriptCore/wtf/HashTable.cpp
@@ -0,0 +1,69 @@
+/*
+    Copyright (C) 2005 Apple Inc. All rights reserved.
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Library General Public
+    License as published by the Free Software Foundation; either
+    version 2 of the License, or (at your option) any later version.
+
+    This library 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
+    Library General Public License for more details.
+
+    You should have received a copy of the GNU Library General Public License
+    along with this library; see the file COPYING.LIB.  If not, write to
+    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+    Boston, MA 02110-1301, USA.
+*/
+
+#include "config.h"
+#include "HashTable.h"
+
+namespace WTF {
+
+#if DUMP_HASHTABLE_STATS
+
+int HashTableStats::numAccesses;
+int HashTableStats::numCollisions;
+int HashTableStats::collisionGraph[4096];
+int HashTableStats::maxCollisions;
+int HashTableStats::numRehashes;
+int HashTableStats::numRemoves;
+int HashTableStats::numReinserts;
+
+static HashTableStats logger;
+
+static Mutex& hashTableStatsMutex()
+{
+    AtomicallyInitializedStatic(Mutex&, mutex = *new Mutex);
+    return mutex;
+}
+
+HashTableStats::~HashTableStats()
+{
+    // Don't lock hashTableStatsMutex here because it can cause deadlocks at shutdown 
+    // if any thread was killed while holding the mutex.
+    printf("\nWTF::HashTable statistics\n\n");
+    printf("%d accesses\n", numAccesses);
+    printf("%d total collisions, average %.2f probes per access\n", numCollisions, 1.0 * (numAccesses + numCollisions) / numAccesses);
+    printf("longest collision chain: %d\n", maxCollisions);
+    for (int i = 1; i <= maxCollisions; i++) {
+        printf("  %d lookups with exactly %d collisions (%.2f%% , %.2f%% with this many or more)\n", collisionGraph[i], i, 100.0 * (collisionGraph[i] - collisionGraph[i+1]) / numAccesses, 100.0 * collisionGraph[i] / numAccesses);
+    }
+    printf("%d rehashes\n", numRehashes);
+    printf("%d reinserts\n", numReinserts);
+}
+
+void HashTableStats::recordCollisionAtCount(int count)
+{
+    MutexLocker lock(hashTableStatsMutex());
+    if (count > maxCollisions)
+        maxCollisions = count;
+    numCollisions++;
+    collisionGraph[count]++;
+}
+
+#endif
+
+} // namespace WTF