| /* |
| 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 "third_party/blink/renderer/platform/wtf/hash_table.h" |
| |
| #if DUMP_HASHTABLE_STATS || DUMP_HASHTABLE_STATS_PER_TABLE |
| |
| #include <iomanip> |
| #include "third_party/blink/renderer/platform/wtf/threading_primitives.h" |
| |
| namespace WTF { |
| |
| static Mutex& hashTableStatsMutex() { |
| DEFINE_THREAD_SAFE_STATIC_LOCAL(Mutex, mutex, ()); |
| return mutex; |
| } |
| |
| HashTableStats& HashTableStats::instance() { |
| DEFINE_THREAD_SAFE_STATIC_LOCAL(HashTableStats, stats, ()); |
| return stats; |
| } |
| |
| void HashTableStats::copy(const HashTableStats* other) { |
| numAccesses = other->numAccesses.load(std::memory_order_relaxed); |
| numRehashes = other->numRehashes.load(std::memory_order_relaxed); |
| numRemoves = other->numRemoves.load(std::memory_order_relaxed); |
| numReinserts = other->numReinserts.load(std::memory_order_relaxed); |
| |
| maxCollisions = other->maxCollisions; |
| numCollisions = other->numCollisions; |
| memcpy(collisionGraph, other->collisionGraph, sizeof(collisionGraph)); |
| } |
| |
| void HashTableStats::recordCollisionAtCount(int count) { |
| // The global hash table singleton needs to be atomically updated. |
| if (this == &instance()) { |
| MutexLocker locker(hashTableStatsMutex()); |
| RecordCollisionAtCountWithoutLock(count); |
| } else { |
| RecordCollisionAtCountWithoutLock(count); |
| } |
| } |
| |
| void HashTableStats::RecordCollisionAtCountWithoutLock(int count) { |
| if (count > maxCollisions) |
| maxCollisions = count; |
| numCollisions++; |
| collisionGraph[count]++; |
| } |
| |
| void HashTableStats::DumpStats() { |
| // Lock the global hash table singleton while dumping. |
| if (this == &instance()) { |
| MutexLocker locker(hashTableStatsMutex()); |
| DumpStatsWithoutLock(); |
| } else { |
| DumpStatsWithoutLock(); |
| } |
| } |
| |
| void HashTableStats::DumpStatsWithoutLock() { |
| std::stringstream collision_str; |
| collision_str << std::fixed << std::setprecision(2); |
| for (int i = 1; i <= maxCollisions; i++) { |
| collision_str << " " << collisionGraph[i] << " lookups with exactly " |
| << i << " collisions (" |
| << (100.0 * (collisionGraph[i] - collisionGraph[i + 1]) / |
| numAccesses) |
| << "% , " << (100.0 * collisionGraph[i] / numAccesses) |
| << "% with this many or more)\n"; |
| } |
| |
| DLOG(INFO) << std::fixed << std::setprecision(2) |
| << "WTF::HashTable statistics:\n" |
| << " " << numAccesses << " accesses\n" |
| << " " << numCollisions << " total collisions, average " |
| << (1.0 * (numAccesses + numCollisions) / numAccesses) |
| << " probes per access\n" |
| << " longest collision chain: " << maxCollisions << "\n" |
| << collision_str.str() << " " << numRehashes << " rehashes\n" |
| << " " << numReinserts << " reinserts"; |
| } |
| |
| } // namespace WTF |
| |
| #endif |