Mercurial > hg > graal-compiler
annotate src/share/vm/utilities/hashtable.cpp @ 1711:a6bff45449bc
6973570: OrderAccess::storestore() scales poorly on multi-socket x64 and sparc: cache-line ping-ponging
Summary: volatile store to static variable removed in favour of a volatile store to stack to avoid excessive cache coherency traffic; verified that the volatile store is not elided by any of our current compilers.
Reviewed-by: dholmes, dice, jcoomes, kvn
author | ysr |
---|---|
date | Tue, 10 Aug 2010 14:53:35 -0700 |
parents | c18cbe5936b8 |
children | f95d63e2154a |
rev | line source |
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0 | 1 /* |
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2 * Copyright (c) 2003, 2008, Oracle and/or its affiliates. All rights reserved. |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
25 # include "incls/_precompiled.incl" | |
26 # include "incls/_hashtable.cpp.incl" | |
27 | |
28 HS_DTRACE_PROBE_DECL4(hs_private, hashtable__new_entry, | |
29 void*, unsigned int, oop, void*); | |
30 | |
31 // This is a generic hashtable, designed to be used for the symbol | |
32 // and string tables. | |
33 // | |
34 // It is implemented as an open hash table with a fixed number of buckets. | |
35 // | |
36 // %note: | |
37 // - HashtableEntrys are allocated in blocks to reduce the space overhead. | |
38 | |
39 BasicHashtableEntry* BasicHashtable::new_entry(unsigned int hashValue) { | |
40 BasicHashtableEntry* entry; | |
41 | |
42 if (_free_list) { | |
43 entry = _free_list; | |
44 _free_list = _free_list->next(); | |
45 } else { | |
432 | 46 if (_first_free_entry + _entry_size >= _end_block) { |
47 int block_size = MIN2(512, MAX2((int)_table_size / 2, (int)_number_of_entries)); | |
0 | 48 int len = _entry_size * block_size; |
432 | 49 len = 1 << log2_intptr(len); // round down to power of 2 |
50 assert(len >= _entry_size, ""); | |
0 | 51 _first_free_entry = NEW_C_HEAP_ARRAY(char, len); |
52 _end_block = _first_free_entry + len; | |
53 } | |
54 entry = (BasicHashtableEntry*)_first_free_entry; | |
55 _first_free_entry += _entry_size; | |
56 } | |
57 | |
432 | 58 assert(_entry_size % HeapWordSize == 0, ""); |
0 | 59 entry->set_hash(hashValue); |
60 return entry; | |
61 } | |
62 | |
63 | |
64 HashtableEntry* Hashtable::new_entry(unsigned int hashValue, oop obj) { | |
65 HashtableEntry* entry; | |
66 | |
67 entry = (HashtableEntry*)BasicHashtable::new_entry(hashValue); | |
68 entry->set_literal(obj); // clears literal string field | |
69 HS_DTRACE_PROBE4(hs_private, hashtable__new_entry, | |
70 this, hashValue, obj, entry); | |
71 return entry; | |
72 } | |
73 | |
74 | |
75 // GC support | |
76 | |
77 void Hashtable::unlink(BoolObjectClosure* is_alive) { | |
78 // Readers of the table are unlocked, so we should only be removing | |
79 // entries at a safepoint. | |
80 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); | |
81 for (int i = 0; i < table_size(); ++i) { | |
82 for (HashtableEntry** p = bucket_addr(i); *p != NULL; ) { | |
83 HashtableEntry* entry = *p; | |
84 if (entry->is_shared()) { | |
85 break; | |
86 } | |
87 assert(entry->literal() != NULL, "just checking"); | |
88 if (is_alive->do_object_b(entry->literal())) { | |
89 p = entry->next_addr(); | |
90 } else { | |
91 *p = entry->next(); | |
92 free_entry(entry); | |
93 } | |
94 } | |
95 } | |
96 } | |
97 | |
98 | |
99 void Hashtable::oops_do(OopClosure* f) { | |
100 for (int i = 0; i < table_size(); ++i) { | |
101 HashtableEntry** p = bucket_addr(i); | |
102 HashtableEntry* entry = bucket(i); | |
103 while (entry != NULL) { | |
104 f->do_oop(entry->literal_addr()); | |
105 | |
106 // Did the closure remove the literal from the table? | |
107 if (entry->literal() == NULL) { | |
108 assert(!entry->is_shared(), "immutable hashtable entry?"); | |
109 *p = entry->next(); | |
110 free_entry(entry); | |
111 } else { | |
112 p = entry->next_addr(); | |
113 } | |
114 entry = (HashtableEntry*)HashtableEntry::make_ptr(*p); | |
115 } | |
116 } | |
117 } | |
118 | |
119 | |
120 // Reverse the order of elements in the hash buckets. | |
121 | |
122 void BasicHashtable::reverse() { | |
123 | |
124 for (int i = 0; i < _table_size; ++i) { | |
125 BasicHashtableEntry* new_list = NULL; | |
126 BasicHashtableEntry* p = bucket(i); | |
127 while (p != NULL) { | |
128 BasicHashtableEntry* next = p->next(); | |
129 p->set_next(new_list); | |
130 new_list = p; | |
131 p = next; | |
132 } | |
133 *bucket_addr(i) = new_list; | |
134 } | |
135 } | |
136 | |
137 | |
138 // Copy the table to the shared space. | |
139 | |
140 void BasicHashtable::copy_table(char** top, char* end) { | |
141 | |
142 // Dump the hash table entries. | |
143 | |
144 intptr_t *plen = (intptr_t*)(*top); | |
145 *top += sizeof(*plen); | |
146 | |
147 int i; | |
148 for (i = 0; i < _table_size; ++i) { | |
149 for (BasicHashtableEntry** p = _buckets[i].entry_addr(); | |
150 *p != NULL; | |
151 p = (*p)->next_addr()) { | |
152 if (*top + entry_size() > end) { | |
153 warning("\nThe shared miscellaneous data space is not large " | |
154 "enough to \npreload requested classes. Use " | |
155 "-XX:SharedMiscDataSize= to increase \nthe initial " | |
156 "size of the miscellaneous data space.\n"); | |
157 exit(2); | |
158 } | |
159 *p = (BasicHashtableEntry*)memcpy(*top, *p, entry_size()); | |
160 *top += entry_size(); | |
161 } | |
162 } | |
163 *plen = (char*)(*top) - (char*)plen - sizeof(*plen); | |
164 | |
165 // Set the shared bit. | |
166 | |
167 for (i = 0; i < _table_size; ++i) { | |
168 for (BasicHashtableEntry* p = bucket(i); p != NULL; p = p->next()) { | |
169 p->set_shared(); | |
170 } | |
171 } | |
172 } | |
173 | |
174 | |
175 | |
176 // Reverse the order of elements in the hash buckets. | |
177 | |
178 void Hashtable::reverse(void* boundary) { | |
179 | |
180 for (int i = 0; i < table_size(); ++i) { | |
181 HashtableEntry* high_list = NULL; | |
182 HashtableEntry* low_list = NULL; | |
183 HashtableEntry* last_low_entry = NULL; | |
184 HashtableEntry* p = bucket(i); | |
185 while (p != NULL) { | |
186 HashtableEntry* next = p->next(); | |
187 if ((void*)p->literal() >= boundary) { | |
188 p->set_next(high_list); | |
189 high_list = p; | |
190 } else { | |
191 p->set_next(low_list); | |
192 low_list = p; | |
193 if (last_low_entry == NULL) { | |
194 last_low_entry = p; | |
195 } | |
196 } | |
197 p = next; | |
198 } | |
199 if (low_list != NULL) { | |
200 *bucket_addr(i) = low_list; | |
201 last_low_entry->set_next(high_list); | |
202 } else { | |
203 *bucket_addr(i) = high_list; | |
204 } | |
205 } | |
206 } | |
207 | |
208 | |
209 // Dump the hash table buckets. | |
210 | |
211 void BasicHashtable::copy_buckets(char** top, char* end) { | |
212 intptr_t len = _table_size * sizeof(HashtableBucket); | |
213 *(intptr_t*)(*top) = len; | |
214 *top += sizeof(intptr_t); | |
215 | |
216 *(intptr_t*)(*top) = _number_of_entries; | |
217 *top += sizeof(intptr_t); | |
218 | |
219 if (*top + len > end) { | |
220 warning("\nThe shared miscellaneous data space is not large " | |
221 "enough to \npreload requested classes. Use " | |
222 "-XX:SharedMiscDataSize= to increase \nthe initial " | |
223 "size of the miscellaneous data space.\n"); | |
224 exit(2); | |
225 } | |
226 _buckets = (HashtableBucket*)memcpy(*top, _buckets, len); | |
227 *top += len; | |
228 } | |
229 | |
230 | |
231 #ifndef PRODUCT | |
232 | |
233 void Hashtable::print() { | |
234 ResourceMark rm; | |
235 | |
236 for (int i = 0; i < table_size(); i++) { | |
237 HashtableEntry* entry = bucket(i); | |
238 while(entry != NULL) { | |
239 tty->print("%d : ", i); | |
240 entry->literal()->print(); | |
241 tty->cr(); | |
242 entry = entry->next(); | |
243 } | |
244 } | |
245 } | |
246 | |
247 | |
248 void BasicHashtable::verify() { | |
249 int count = 0; | |
250 for (int i = 0; i < table_size(); i++) { | |
251 for (BasicHashtableEntry* p = bucket(i); p != NULL; p = p->next()) { | |
252 ++count; | |
253 } | |
254 } | |
255 assert(count == number_of_entries(), "number of hashtable entries incorrect"); | |
256 } | |
257 | |
258 | |
259 #endif // PRODUCT | |
260 | |
261 | |
262 #ifdef ASSERT | |
263 | |
264 void BasicHashtable::verify_lookup_length(double load) { | |
265 if ((double)_lookup_length / (double)_lookup_count > load * 2.0) { | |
266 warning("Performance bug: SystemDictionary lookup_count=%d " | |
267 "lookup_length=%d average=%lf load=%f", | |
268 _lookup_count, _lookup_length, | |
269 (double) _lookup_length / _lookup_count, load); | |
270 } | |
271 } | |
272 | |
273 #endif |