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 23 namespace WTF { 24 25 #if DUMP_HASHTABLE_STATS 26 27 int HashTableStats::numAccesses; 28 int HashTableStats::numCollisions; 29 int HashTableStats::collisionGraph[4096]; 30 int HashTableStats::maxCollisions; 31 int HashTableStats::numRehashes; 32 int HashTableStats::numRemoves; 33 int HashTableStats::numReinserts; 34 35 static HashTableStats logger; 36 37 static Mutex& hashTableStatsMutex() 38 { 39 AtomicallyInitializedStatic(Mutex&, mutex = *new Mutex); 40 return mutex; 41 } 42 43 HashTableStats::~HashTableStats() 44 { 45 // Don't lock hashTableStatsMutex here because it can cause deadlocks at shutdown 46 // if any thread was killed while holding the mutex. 47 printf("\nWTF::HashTable statistics\n\n"); 48 printf("%d accesses\n", numAccesses); 49 printf("%d total collisions, average %.2f probes per access\n", numCollisions, 1.0 * (numAccesses + numCollisions) / numAccesses); 50 printf("longest collision chain: %d\n", maxCollisions); 51 for (int i = 1; i <= maxCollisions; i++) { 52 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); 53 } 54 printf("%d rehashes\n", numRehashes); 55 printf("%d reinserts\n", numReinserts); 56 } 57 58 void HashTableStats::recordCollisionAtCount(int count) 59 { 60 MutexLocker lock(hashTableStatsMutex()); 61 if (count > maxCollisions) 62 maxCollisions = count; 63 numCollisions++; 64 collisionGraph[count]++; 65 } 66 67 #endif 68 69 } // namespace WTF 70
