1 /*
2 * Copyright (c) 2014, 2020, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/altHashing.hpp"
27 #include "classfile/javaClasses.inline.hpp"
28 #include "gc/shared/stringdedup/stringDedup.hpp"
29 #include "gc/shared/stringdedup/stringDedupTable.hpp"
30 #include "gc/shared/suspendibleThreadSet.hpp"
31 #include "logging/log.hpp"
32 #include "memory/padded.inline.hpp"
33 #include "memory/universe.hpp"
34 #include "oops/access.inline.hpp"
35 #include "oops/arrayOop.inline.hpp"
36 #include "oops/oop.inline.hpp"
37 #include "oops/typeArrayOop.hpp"
38 #include "runtime/atomic.hpp"
39 #include "runtime/mutexLocker.hpp"
40 #include "runtime/safepointVerifiers.hpp"
41
42 //
43 // List of deduplication table entries. Links table
44 // entries together using their _next fields.
45 //
46 class StringDedupEntryList : public CHeapObj<mtGC> {
47 private:
48 StringDedupEntry* _list;
49 size_t _length;
50
51 public:
52 StringDedupEntryList() :
53 _list(NULL),
54 _length(0) {
55 }
56
57 void add(StringDedupEntry* entry) {
58 entry->set_next(_list);
59 _list = entry;
60 _length++;
61 }
62
63 StringDedupEntry* remove() {
64 StringDedupEntry* entry = _list;
65 if (entry != NULL) {
66 _list = entry->next();
67 _length--;
68 }
69 return entry;
70 }
71
72 StringDedupEntry* remove_all() {
73 StringDedupEntry* list = _list;
74 _list = NULL;
75 return list;
76 }
77
78 size_t length() {
79 return _length;
80 }
81 };
82
83 //
84 // Cache of deduplication table entries. This cache provides fast allocation and
85 // reuse of table entries to lower the pressure on the underlying allocator.
86 // But more importantly, it provides fast/deferred freeing of table entries. This
87 // is important because freeing of table entries is done during stop-the-world
88 // phases and it is not uncommon for large number of entries to be freed at once.
89 // Tables entries that are freed during these phases are placed onto a freelist in
90 // the cache. The deduplication thread, which executes in a concurrent phase, will
91 // later reuse or free the underlying memory for these entries.
92 //
93 // The cache allows for single-threaded allocations and multi-threaded frees.
94 // Allocations are synchronized by StringDedupTable_lock as part of a table
95 // modification.
96 //
97 class StringDedupEntryCache : public CHeapObj<mtGC> {
98 private:
99 // One cache/overflow list per GC worker to allow lock less freeing of
100 // entries while doing a parallel scan of the table. Using PaddedEnd to
101 // avoid false sharing.
102 size_t _nlists;
103 size_t _max_list_length;
104 PaddedEnd<StringDedupEntryList>* _cached;
105 PaddedEnd<StringDedupEntryList>* _overflowed;
106
107 public:
108 StringDedupEntryCache(size_t max_size);
109 ~StringDedupEntryCache();
110
111 // Set max number of table entries to cache.
112 void set_max_size(size_t max_size);
113
114 // Get a table entry from the cache, or allocate a new entry if the cache is empty.
115 StringDedupEntry* alloc();
116
117 // Insert a table entry into the cache.
118 void free(StringDedupEntry* entry, uint worker_id);
119
120 // Returns current number of entries in the cache.
121 size_t size();
122
123 // Deletes overflowed entries.
124 void delete_overflowed();
125 };
126
127 StringDedupEntryCache::StringDedupEntryCache(size_t max_size) :
128 _nlists(ParallelGCThreads),
129 _max_list_length(0),
130 _cached(PaddedArray<StringDedupEntryList, mtGC>::create_unfreeable((uint)_nlists)),
131 _overflowed(PaddedArray<StringDedupEntryList, mtGC>::create_unfreeable((uint)_nlists)) {
132 set_max_size(max_size);
133 }
134
135 StringDedupEntryCache::~StringDedupEntryCache() {
136 ShouldNotReachHere();
137 }
138
139 void StringDedupEntryCache::set_max_size(size_t size) {
140 _max_list_length = size / _nlists;
141 }
142
143 StringDedupEntry* StringDedupEntryCache::alloc() {
144 for (size_t i = 0; i < _nlists; i++) {
145 StringDedupEntry* entry = _cached[i].remove();
146 if (entry != NULL) {
147 return entry;
148 }
149 }
150 return new StringDedupEntry();
151 }
152
153 void StringDedupEntryCache::free(StringDedupEntry* entry, uint worker_id) {
154 assert(entry->obj() != NULL, "Double free");
155 assert(worker_id < _nlists, "Invalid worker id");
156
157 entry->set_obj(NULL);
158 entry->set_hash(0);
159
160 if (_cached[worker_id].length() < _max_list_length) {
161 // Cache is not full
162 _cached[worker_id].add(entry);
163 } else {
164 // Cache is full, add to overflow list for later deletion
165 _overflowed[worker_id].add(entry);
166 }
167 }
168
169 size_t StringDedupEntryCache::size() {
170 size_t size = 0;
171 for (size_t i = 0; i < _nlists; i++) {
172 size += _cached[i].length();
173 }
174 return size;
175 }
176
177 void StringDedupEntryCache::delete_overflowed() {
178 double start = os::elapsedTime();
179 uintx count = 0;
180
181 for (size_t i = 0; i < _nlists; i++) {
182 StringDedupEntry* entry;
183
184 {
185 // The overflow list can be modified during safepoints, therefore
186 // we temporarily join the suspendible thread set while removing
187 // all entries from the list.
188 SuspendibleThreadSetJoiner sts_join;
189 entry = _overflowed[i].remove_all();
190 }
191
192 // Delete all entries
193 while (entry != NULL) {
194 StringDedupEntry* next = entry->next();
195 delete entry;
196 entry = next;
197 count++;
198 }
199 }
200
201 double end = os::elapsedTime();
202 log_trace(gc, stringdedup)("Deleted " UINTX_FORMAT " entries, " STRDEDUP_TIME_FORMAT_MS,
203 count, STRDEDUP_TIME_PARAM_MS(end - start));
204 }
205
206 StringDedupTable* StringDedupTable::_table = NULL;
207 StringDedupEntryCache* StringDedupTable::_entry_cache = NULL;
208
209 const size_t StringDedupTable::_min_size = (1 << 10); // 1024
210 const size_t StringDedupTable::_max_size = (1 << 24); // 16777216
211 const double StringDedupTable::_grow_load_factor = 2.0; // Grow table at 200% load
212 const double StringDedupTable::_shrink_load_factor = _grow_load_factor / 3.0; // Shrink table at 67% load
213 const double StringDedupTable::_max_cache_factor = 0.1; // Cache a maximum of 10% of the table size
214 const uintx StringDedupTable::_rehash_multiple = 60; // Hash bucket has 60 times more collisions than expected
215 const uintx StringDedupTable::_rehash_threshold = (uintx)(_rehash_multiple * _grow_load_factor);
216
217 uintx StringDedupTable::_entries_added = 0;
218 volatile uintx StringDedupTable::_entries_removed = 0;
219 uintx StringDedupTable::_resize_count = 0;
220 uintx StringDedupTable::_rehash_count = 0;
221
222 StringDedupTable* StringDedupTable::_resized_table = NULL;
223 StringDedupTable* StringDedupTable::_rehashed_table = NULL;
224 volatile size_t StringDedupTable::_claimed_index = 0;
225
226 StringDedupTable::StringDedupTable(size_t size, jint hash_seed) :
227 _size(size),
228 _entries(0),
229 _shrink_threshold((uintx)(size * _shrink_load_factor)),
230 _grow_threshold((uintx)(size * _grow_load_factor)),
231 _rehash_needed(false),
232 _hash_seed(hash_seed) {
233 assert(is_power_of_2(size), "Table size must be a power of 2");
234 _buckets = NEW_C_HEAP_ARRAY(StringDedupEntry*, _size, mtGC);
235 memset(_buckets, 0, _size * sizeof(StringDedupEntry*));
236 }
237
238 StringDedupTable::~StringDedupTable() {
239 FREE_C_HEAP_ARRAY(G1StringDedupEntry*, _buckets);
240 }
241
242 void StringDedupTable::create() {
243 assert(_table == NULL, "One string deduplication table allowed");
244 _entry_cache = new StringDedupEntryCache(_min_size * _max_cache_factor);
245 _table = new StringDedupTable(_min_size);
246 }
247
248 void StringDedupTable::add(typeArrayOop value, bool latin1, unsigned int hash, StringDedupEntry** list) {
249 StringDedupEntry* entry = _entry_cache->alloc();
250 entry->set_obj(value);
251 entry->set_hash(hash);
252 entry->set_latin1(latin1);
253 entry->set_next(*list);
254 *list = entry;
255 _entries++;
256 }
257
258 void StringDedupTable::remove(StringDedupEntry** pentry, uint worker_id) {
259 StringDedupEntry* entry = *pentry;
260 *pentry = entry->next();
261 _entry_cache->free(entry, worker_id);
262 }
263
264 void StringDedupTable::transfer(StringDedupEntry** pentry, StringDedupTable* dest) {
265 StringDedupEntry* entry = *pentry;
266 *pentry = entry->next();
267 unsigned int hash = entry->hash();
268 size_t index = dest->hash_to_index(hash);
269 StringDedupEntry** list = dest->bucket(index);
270 entry->set_next(*list);
271 *list = entry;
272 }
273
274 typeArrayOop StringDedupTable::lookup(typeArrayOop value, bool latin1, unsigned int hash,
275 StringDedupEntry** list, uintx &count) {
276 for (StringDedupEntry* entry = *list; entry != NULL; entry = entry->next()) {
277 if (entry->hash() == hash && entry->latin1() == latin1) {
278 oop* obj_addr = (oop*)entry->obj_addr();
279 oop obj = NativeAccess<ON_PHANTOM_OOP_REF | AS_NO_KEEPALIVE>::oop_load(obj_addr);
280 if (java_lang_String::value_equals(value, static_cast<typeArrayOop>(obj))) {
281 obj = NativeAccess<ON_PHANTOM_OOP_REF>::oop_load(obj_addr);
282 return static_cast<typeArrayOop>(obj);
283 }
284 }
285 count++;
286 }
287
288 // Not found
289 return NULL;
290 }
291
292 typeArrayOop StringDedupTable::lookup_or_add_inner(typeArrayOop value, bool latin1, unsigned int hash) {
293 size_t index = hash_to_index(hash);
294 StringDedupEntry** list = bucket(index);
295 uintx count = 0;
296
297 // Lookup in list
298 typeArrayOop existing_value = lookup(value, latin1, hash, list, count);
299
300 // Check if rehash is needed
301 if (count > _rehash_threshold) {
302 _rehash_needed = true;
303 }
304
305 if (existing_value == NULL) {
306 // Not found, add new entry
307 add(value, latin1, hash, list);
308
309 // Update statistics
310 _entries_added++;
311 }
312
313 return existing_value;
314 }
315
316 unsigned int StringDedupTable::hash_code(typeArrayOop value, bool latin1) {
317 unsigned int hash;
318 int length = value->length();
319 if (latin1) {
320 const jbyte* data = (jbyte*)value->base(T_BYTE);
321 if (use_java_hash()) {
322 hash = java_lang_String::hash_code(data, length);
323 } else {
324 hash = AltHashing::murmur3_32(_table->_hash_seed, data, length);
325 }
326 } else {
327 length /= sizeof(jchar) / sizeof(jbyte); // Convert number of bytes to number of chars
328 const jchar* data = (jchar*)value->base(T_CHAR);
329 if (use_java_hash()) {
330 hash = java_lang_String::hash_code(data, length);
331 } else {
332 hash = AltHashing::murmur3_32(_table->_hash_seed, data, length);
333 }
334 }
335
336 return hash;
337 }
338
339 void StringDedupTable::deduplicate(oop java_string, StringDedupStat* stat) {
340 assert(java_lang_String::is_instance(java_string), "Must be a string");
341 NoSafepointVerifier nsv;
342
343 stat->inc_inspected();
344
345 typeArrayOop value = java_lang_String::value(java_string);
346 if (value == NULL) {
347 // String has no value
348 stat->inc_skipped();
349 return;
350 }
351
352 bool latin1 = java_lang_String::is_latin1(java_string);
353 unsigned int hash = 0;
354
355 if (use_java_hash()) {
356 if (!java_lang_String::hash_is_set(java_string)) {
357 stat->inc_hashed();
358 }
359 hash = java_lang_String::hash_code(java_string);
360 } else {
361 // Compute hash
362 hash = hash_code(value, latin1);
363 stat->inc_hashed();
364 }
365
366 typeArrayOop existing_value = lookup_or_add(value, latin1, hash);
367 if (existing_value == value) {
368 // Same value, already known
369 stat->inc_known();
370 return;
371 }
372
373 // Get size of value array
374 uintx size_in_bytes = value->size() * HeapWordSize;
375 stat->inc_new(size_in_bytes);
376
377 if (existing_value != NULL) {
378 // Existing value found, deduplicate string
379 java_lang_String::set_value(java_string, existing_value);
380 stat->deduped(value, size_in_bytes);
381 }
382 }
383
384 bool StringDedupTable::is_resizing() {
385 return _resized_table != NULL;
386 }
387
388 bool StringDedupTable::is_rehashing() {
389 return _rehashed_table != NULL;
390 }
391
392 StringDedupTable* StringDedupTable::prepare_resize() {
393 size_t size = _table->_size;
394
395 // Check if the hashtable needs to be resized
396 if (_table->_entries > _table->_grow_threshold) {
397 // Grow table, double the size
398 size *= 2;
399 if (size > _max_size) {
400 // Too big, don't resize
401 return NULL;
402 }
403 } else if (_table->_entries < _table->_shrink_threshold) {
404 // Shrink table, half the size
405 size /= 2;
406 if (size < _min_size) {
407 // Too small, don't resize
408 return NULL;
409 }
410 } else if (StringDeduplicationResizeALot) {
411 // Force grow
412 size *= 2;
413 if (size > _max_size) {
414 // Too big, force shrink instead
415 size /= 4;
416 }
417 } else {
418 // Resize not needed
419 return NULL;
420 }
421
422 // Update statistics
423 _resize_count++;
424
425 // Update max cache size
426 _entry_cache->set_max_size(size * _max_cache_factor);
427
428 // Allocate the new table. The new table will be populated by workers
429 // calling unlink_or_oops_do() and finally installed by finish_resize().
430 return new StringDedupTable(size, _table->_hash_seed);
431 }
432
433 void StringDedupTable::finish_resize(StringDedupTable* resized_table) {
434 assert(resized_table != NULL, "Invalid table");
435
436 resized_table->_entries = _table->_entries;
437
438 // Free old table
439 delete _table;
440
441 // Install new table
442 _table = resized_table;
443 }
444
445 void StringDedupTable::unlink_or_oops_do(StringDedupUnlinkOrOopsDoClosure* cl, uint worker_id) {
446 // The table is divided into partitions to allow lock-less parallel processing by
447 // multiple worker threads. A worker thread first claims a partition, which ensures
448 // exclusive access to that part of the table, then continues to process it. To allow
449 // shrinking of the table in parallel we also need to make sure that the same worker
450 // thread processes all partitions where entries will hash to the same destination
451 // partition. Since the table size is always a power of two and we always shrink by
452 // dividing the table in half, we know that for a given partition there is only one
453 // other partition whoes entries will hash to the same destination partition. That
454 // other partition is always the sibling partition in the second half of the table.
455 // For example, if the table is divided into 8 partitions, the sibling of partition 0
456 // is partition 4, the sibling of partition 1 is partition 5, etc.
457 size_t table_half = _table->_size / 2;
458
459 // Let each partition be one page worth of buckets
460 size_t partition_size = MIN2(table_half, os::vm_page_size() / sizeof(StringDedupEntry*));
461 assert(table_half % partition_size == 0, "Invalid partition size");
462
463 // Number of entries removed during the scan
464 uintx removed = 0;
465
466 for (;;) {
467 // Grab next partition to scan
468 size_t partition_begin = claim_table_partition(partition_size);
469 size_t partition_end = partition_begin + partition_size;
470 if (partition_begin >= table_half) {
471 // End of table
472 break;
473 }
474
475 // Scan the partition followed by the sibling partition in the second half of the table
476 removed += unlink_or_oops_do(cl, partition_begin, partition_end, worker_id);
477 removed += unlink_or_oops_do(cl, table_half + partition_begin, table_half + partition_end, worker_id);
478 }
479
480 // Delayed update to avoid contention on the table lock
481 if (removed > 0) {
482 assert_locked_or_safepoint_weak(StringDedupTable_lock);
483 Atomic::sub(&_table->_entries, removed);
484 Atomic::add(&_entries_removed, removed);
485 }
486 }
487
488 uintx StringDedupTable::unlink_or_oops_do(StringDedupUnlinkOrOopsDoClosure* cl,
489 size_t partition_begin,
490 size_t partition_end,
491 uint worker_id) {
492 uintx removed = 0;
493 for (size_t bucket = partition_begin; bucket < partition_end; bucket++) {
494 StringDedupEntry** entry = _table->bucket(bucket);
495 while (*entry != NULL) {
496 oop* p = (oop*)(*entry)->obj_addr();
497 if (cl->is_alive(*p)) {
498 cl->keep_alive(p);
499 if (is_resizing()) {
500 // We are resizing the table, transfer entry to the new table
501 _table->transfer(entry, _resized_table);
502 } else {
503 if (is_rehashing()) {
504 // We are rehashing the table, rehash the entry but keep it
505 // in the table. We can't transfer entries into the new table
506 // at this point since we don't have exclusive access to all
507 // destination partitions. finish_rehash() will do a single
508 // threaded transfer of all entries.
509 typeArrayOop value = (typeArrayOop)*p;
510 bool latin1 = (*entry)->latin1();
511 unsigned int hash = hash_code(value, latin1);
512 (*entry)->set_hash(hash);
513 }
514
515 // Move to next entry
516 entry = (*entry)->next_addr();
517 }
518 } else {
519 // Not alive, remove entry from table
520 _table->remove(entry, worker_id);
521 removed++;
522 }
523 }
524 }
525
526 return removed;
527 }
528
529 void StringDedupTable::gc_prologue(bool resize_and_rehash_table) {
530 assert(!is_resizing() && !is_rehashing(), "Already in progress?");
531
532 _claimed_index = 0;
533 if (resize_and_rehash_table) {
534 // If both resize and rehash is needed, only do resize. Rehash of
535 // the table will eventually happen if the situation persists.
536 _resized_table = StringDedupTable::prepare_resize();
537 if (!is_resizing()) {
538 _rehashed_table = StringDedupTable::prepare_rehash();
539 }
540 }
541 }
542
543 void StringDedupTable::gc_epilogue() {
544 assert(!is_resizing() || !is_rehashing(), "Can not both resize and rehash");
545 assert(_claimed_index >= _table->_size / 2 || _claimed_index == 0, "All or nothing");
546
547 if (is_resizing()) {
548 StringDedupTable::finish_resize(_resized_table);
549 _resized_table = NULL;
550 } else if (is_rehashing()) {
551 StringDedupTable::finish_rehash(_rehashed_table);
552 _rehashed_table = NULL;
553 }
554 }
555
556 StringDedupTable* StringDedupTable::prepare_rehash() {
557 if (!_table->_rehash_needed && !StringDeduplicationRehashALot) {
558 // Rehash not needed
559 return NULL;
560 }
561
562 // Update statistics
563 _rehash_count++;
564
565 // Compute new hash seed
566 _table->_hash_seed = AltHashing::compute_seed();
567
568 // Allocate the new table, same size and hash seed
569 return new StringDedupTable(_table->_size, _table->_hash_seed);
570 }
571
572 void StringDedupTable::finish_rehash(StringDedupTable* rehashed_table) {
573 assert(rehashed_table != NULL, "Invalid table");
574
575 // Move all newly rehashed entries into the correct buckets in the new table
576 for (size_t bucket = 0; bucket < _table->_size; bucket++) {
577 StringDedupEntry** entry = _table->bucket(bucket);
578 while (*entry != NULL) {
579 _table->transfer(entry, rehashed_table);
580 }
581 }
582
583 rehashed_table->_entries = _table->_entries;
584
585 // Free old table
586 delete _table;
587
588 // Install new table
589 _table = rehashed_table;
590 }
591
592 size_t StringDedupTable::claim_table_partition(size_t partition_size) {
593 return Atomic::add(&_claimed_index, partition_size) - partition_size;
594 }
595
596 void StringDedupTable::verify() {
597 for (size_t bucket = 0; bucket < _table->_size; bucket++) {
598 // Verify entries
599 StringDedupEntry** entry = _table->bucket(bucket);
600 while (*entry != NULL) {
601 typeArrayOop value = (*entry)->obj();
602 guarantee(value != NULL, "Object must not be NULL");
603 guarantee(Universe::heap()->is_in(value), "Object must be on the heap");
604 guarantee(!value->is_forwarded(), "Object must not be forwarded");
605 guarantee(value->is_typeArray(), "Object must be a typeArrayOop");
606 bool latin1 = (*entry)->latin1();
607 unsigned int hash = hash_code(value, latin1);
608 guarantee((*entry)->hash() == hash, "Table entry has inorrect hash");
609 guarantee(_table->hash_to_index(hash) == bucket, "Table entry has incorrect index");
610 entry = (*entry)->next_addr();
611 }
612
613 // Verify that we do not have entries with identical oops or identical arrays.
614 // We only need to compare entries in the same bucket. If the same oop or an
615 // identical array has been inserted more than once into different/incorrect
616 // buckets the verification step above will catch that.
617 StringDedupEntry** entry1 = _table->bucket(bucket);
618 while (*entry1 != NULL) {
619 typeArrayOop value1 = (*entry1)->obj();
620 bool latin1_1 = (*entry1)->latin1();
621 StringDedupEntry** entry2 = (*entry1)->next_addr();
622 while (*entry2 != NULL) {
623 typeArrayOop value2 = (*entry2)->obj();
624 bool latin1_2 = (*entry2)->latin1();
625 guarantee(latin1_1 != latin1_2 || !java_lang_String::value_equals(value1, value2), "Table entries must not have identical arrays");
626 entry2 = (*entry2)->next_addr();
627 }
628 entry1 = (*entry1)->next_addr();
629 }
630 }
631 }
632
633 void StringDedupTable::clean_entry_cache() {
634 _entry_cache->delete_overflowed();
635 }
636
637 void StringDedupTable::print_statistics() {
638 Log(gc, stringdedup) log;
639 log.debug(" Table");
640 log.debug(" Memory Usage: " STRDEDUP_BYTES_FORMAT_NS,
641 STRDEDUP_BYTES_PARAM(_table->_size * sizeof(StringDedupEntry*) + (_table->_entries + _entry_cache->size()) * sizeof(StringDedupEntry)));
642 log.debug(" Size: " SIZE_FORMAT ", Min: " SIZE_FORMAT ", Max: " SIZE_FORMAT, _table->_size, _min_size, _max_size);
643 log.debug(" Entries: " UINTX_FORMAT ", Load: " STRDEDUP_PERCENT_FORMAT_NS ", Cached: " UINTX_FORMAT ", Added: " UINTX_FORMAT ", Removed: " UINTX_FORMAT,
644 _table->_entries, percent_of((size_t)_table->_entries, _table->_size), _entry_cache->size(), _entries_added, _entries_removed);
645 log.debug(" Resize Count: " UINTX_FORMAT ", Shrink Threshold: " UINTX_FORMAT "(" STRDEDUP_PERCENT_FORMAT_NS "), Grow Threshold: " UINTX_FORMAT "(" STRDEDUP_PERCENT_FORMAT_NS ")",
646 _resize_count, _table->_shrink_threshold, _shrink_load_factor * 100.0, _table->_grow_threshold, _grow_load_factor * 100.0);
647 log.debug(" Rehash Count: " UINTX_FORMAT ", Rehash Threshold: " UINTX_FORMAT ", Hash Seed: 0x%x", _rehash_count, _rehash_threshold, _table->_hash_seed);
648 log.debug(" Age Threshold: " UINTX_FORMAT, StringDeduplicationAgeThreshold);
649 }