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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 <wtf/HashTable.h>
#include <wtf/NeverDestroyed.h>
namespace WTF {
DEFINE_ALLOCATOR_WITH_HEAP_IDENTIFIER(HashTable);
#if DUMP_HASHTABLE_STATS
std::atomic<unsigned> HashTableStats::numAccesses;
std::atomic<unsigned> HashTableStats::numRehashes;
std::atomic<unsigned> HashTableStats::numRemoves;
std::atomic<unsigned> HashTableStats::numReinserts;
unsigned HashTableStats::numCollisions;
unsigned HashTableStats::collisionGraph[4096];
unsigned HashTableStats::maxCollisions;
static Lock hashTableStatsMutex;
void HashTableStats::recordCollisionAtCount(unsigned count)
{
Locker locker { hashTableStatsMutex };
if (count > maxCollisions)
maxCollisions = count;
numCollisions++;
collisionGraph[count]++;
}
void HashTableStats::dumpStats()
{
Locker locker { hashTableStatsMutex };
dataLogF("\nWTF::HashTable statistics\n\n");
dataLogF("%u accesses\n", numAccesses.load());
dataLogF("%d total collisions, average %.2f probes per access\n", numCollisions, 1.0 * (numAccesses + numCollisions) / numAccesses);
dataLogF("longest collision chain: %d\n", maxCollisions);
for (unsigned i = 1; i <= maxCollisions; i++) {
dataLogF(" %u lookups with exactly %u 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);
}
dataLogF("%d rehashes\n", numRehashes.load());
dataLogF("%d reinserts\n", numReinserts.load());
}
#endif
} // namespace WTF
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