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 23namespace WTF { 24 25#if DUMP_HASHTABLE_STATS 26 27int HashTableStats::numAccesses; 28int HashTableStats::numCollisions; 29int HashTableStats::collisionGraph[4096]; 30int HashTableStats::maxCollisions; 31int HashTableStats::numRehashes; 32int HashTableStats::numRemoves; 33int HashTableStats::numReinserts; 34 35static HashTableStats logger; 36 37static Mutex& hashTableStatsMutex() 38{ 39 AtomicallyInitializedStatic(Mutex&, mutex = *new Mutex); 40 return mutex; 41} 42 43HashTableStats::~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 58void 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