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/*
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
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