| 1 | /* |
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| 2 | Copyright (C) 2005 Apple Inc. All rights reserved. |
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| 3 | |
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| 4 | This library is free software; you can redistribute it and/or |
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| 5 | modify it under the terms of the GNU Library General Public |
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| 6 | License as published by the Free Software Foundation; either |
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| 7 | version 2 of the License, or (at your option) any later version. |
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| 8 | |
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| 9 | This library is distributed in the hope that it will be useful, |
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| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 12 | Library General Public License for more details. |
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| 13 | |
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| 14 | You should have received a copy of the GNU Library General Public License |
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| 15 | along with this library; see the file COPYING.LIB. If not, write to |
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| 16 | the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, |
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| 17 | Boston, MA 02110-1301, USA. |
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| 18 | */ |
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| 19 | |
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| 20 | #include "config.h" |
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| 21 | #include "HashTable.h" |
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| 22 | |
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| 23 | namespace WTF { |
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| 24 | |
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| 25 | #if DUMP_HASHTABLE_STATS |
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| 26 | |
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| 27 | int HashTableStats::numAccesses; |
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| 28 | int HashTableStats::numCollisions; |
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| 29 | int HashTableStats::collisionGraph[4096]; |
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| 30 | int HashTableStats::maxCollisions; |
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| 31 | int HashTableStats::numRehashes; |
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| 32 | int HashTableStats::numRemoves; |
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| 33 | int HashTableStats::numReinserts; |
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| 34 | |
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| 35 | static HashTableStats logger; |
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| 36 | |
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| 37 | static Mutex& hashTableStatsMutex() |
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| 38 | { |
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| 39 | AtomicallyInitializedStatic(Mutex&, mutex = *new Mutex); |
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| 40 | return mutex; |
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| 41 | } |
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| 42 | |
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| 43 | HashTableStats::~HashTableStats() |
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| 44 | { |
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| 45 | // Don't lock hashTableStatsMutex here because it can cause deadlocks at shutdown |
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| 46 | // if any thread was killed while holding the mutex. |
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| 47 | printf("\nWTF::HashTable statistics\n\n" ); |
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| 48 | printf("%d accesses\n" , numAccesses); |
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| 49 | printf("%d total collisions, average %.2f probes per access\n" , numCollisions, 1.0 * (numAccesses + numCollisions) / numAccesses); |
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| 50 | printf("longest collision chain: %d\n" , maxCollisions); |
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| 51 | for (int i = 1; i <= maxCollisions; i++) { |
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| 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); |
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| 53 | } |
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| 54 | printf("%d rehashes\n" , numRehashes); |
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| 55 | printf("%d reinserts\n" , numReinserts); |
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| 56 | } |
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| 57 | |
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| 58 | void HashTableStats::recordCollisionAtCount(int count) |
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| 59 | { |
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| 60 | MutexLocker lock(hashTableStatsMutex()); |
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| 61 | if (count > maxCollisions) |
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| 62 | maxCollisions = count; |
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| 63 | numCollisions++; |
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| 64 | collisionGraph[count]++; |
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| 65 | } |
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| 66 | |
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| 67 | #endif |
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| 68 | |
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| 69 | } // namespace WTF |
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| 70 | |
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