1 /* 2 Copyright (C) 2005 Apple Inc. All rights reserved. 3 4 This library is free software; you can redistribute it and/or 5 modify it under the terms of the GNU Library General Public 6 License as published by the Free Software Foundation; either 7 version 2 of the License, or (at your option) any later version. 8 9 This library is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 Library General Public License for more details. 13 14 You should have received a copy of the GNU Library General Public License 15 along with this library; see the file COPYING.LIB. If not, write to 16 the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, 17 Boston, MA 02110-1301, USA. 18 */ 19 20 #include "config.h" 21 #include "HashTable.h" 22 #include "DataLog.h" 23 24 namespace WTF { 25 26 #if DUMP_HASHTABLE_STATS 27 28 int HashTableStats::numAccesses; 29 int HashTableStats::numCollisions; 30 int HashTableStats::collisionGraph[4096]; 31 int HashTableStats::maxCollisions; 32 int HashTableStats::numRehashes; 33 int HashTableStats::numRemoves; 34 int HashTableStats::numReinserts; 35 36 static Mutex& hashTableStatsMutex() 37 { 38 AtomicallyInitializedStatic(Mutex&, mutex = *new Mutex); 39 return mutex; 40 } 41 42 void HashTableStats::recordCollisionAtCount(int count) 43 { 44 MutexLocker lock(hashTableStatsMutex()); 45 if (count > maxCollisions) 46 maxCollisions = count; 47 numCollisions++; 48 collisionGraph[count]++; 49 } 50 51 void HashTableStats::dumpStats() 52 { 53 MutexLocker lock(hashTableStatsMutex()); 54 55 dataLogF("\nWTF::HashTable statistics\n\n"); 56 dataLogF("%d accesses\n", numAccesses); 57 dataLogF("%d total collisions, average %.2f probes per access\n", numCollisions, 1.0 * (numAccesses + numCollisions) / numAccesses); 58 dataLogF("longest collision chain: %d\n", maxCollisions); 59 for (int i = 1; i <= maxCollisions; i++) { 60 dataLogF(" %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); 61 } 62 dataLogF("%d rehashes\n", numRehashes); 63 dataLogF("%d reinserts\n", numReinserts); 64 } 65 66 #endif 67 68 } // namespace WTF 69
