Mercurial > hg > graal-compiler
comparison src/share/vm/classfile/symbolTable.hpp @ 6162:e9140bf80b4a
7158800: Improve storage of symbol tables
Summary: Use an alternate version of hashing algorithm for symbol string tables and after a certain bucket size to improve performance
Reviewed-by: pbk, kamg, dlong, kvn, fparain
author | coleenp |
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date | Wed, 13 Jun 2012 19:52:59 -0400 |
parents | fc9d8850ab8b |
children | 246d977b51f2 |
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6129:4d399f013e5a | 6162:e9140bf80b4a |
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38 // | 38 // |
39 // %note: | 39 // %note: |
40 // - symbolTableEntrys are allocated in blocks to reduce the space overhead. | 40 // - symbolTableEntrys are allocated in blocks to reduce the space overhead. |
41 | 41 |
42 class BoolObjectClosure; | 42 class BoolObjectClosure; |
43 class outputStream; | |
43 | 44 |
44 | 45 |
45 // Class to hold a newly created or referenced Symbol* temporarily in scope. | 46 // Class to hold a newly created or referenced Symbol* temporarily in scope. |
46 // new_symbol() and lookup() will create a Symbol* if not already in the | 47 // new_symbol() and lookup() will create a Symbol* if not already in the |
47 // symbol table and add to the symbol's reference count. | 48 // symbol table and add to the symbol's reference count. |
76 | 77 |
77 private: | 78 private: |
78 // The symbol table | 79 // The symbol table |
79 static SymbolTable* _the_table; | 80 static SymbolTable* _the_table; |
80 | 81 |
82 // Set if one bucket is out of balance due to hash algorithm deficiency | |
83 static bool _needs_rehashing; | |
84 static jint _seed; | |
85 | |
81 // For statistics | 86 // For statistics |
82 static int symbols_removed; | 87 static int symbols_removed; |
83 static int symbols_counted; | 88 static int symbols_counted; |
84 | 89 |
85 Symbol* allocate_symbol(const u1* name, int len, bool c_heap, TRAPS); // Assumes no characters larger than 0x7F | 90 Symbol* allocate_symbol(const u1* name, int len, bool c_heap, TRAPS); // Assumes no characters larger than 0x7F |
117 // Arena for permanent symbols (null class loader) that are never unloaded | 122 // Arena for permanent symbols (null class loader) that are never unloaded |
118 static Arena* _arena; | 123 static Arena* _arena; |
119 static Arena* arena() { return _arena; } // called for statistics | 124 static Arena* arena() { return _arena; } // called for statistics |
120 | 125 |
121 static void initialize_symbols(int arena_alloc_size = 0); | 126 static void initialize_symbols(int arena_alloc_size = 0); |
127 | |
128 static bool use_alternate_hashcode() { return _seed != 0; } | |
129 static jint seed() { return _seed; } | |
130 | |
131 unsigned int new_hash(Symbol* sym); | |
122 public: | 132 public: |
123 enum { | 133 enum { |
124 symbol_alloc_batch_size = 8, | 134 symbol_alloc_batch_size = 8, |
125 // Pick initial size based on java -version size measurements | 135 // Pick initial size based on java -version size measurements |
126 symbol_alloc_arena_size = 360*K | 136 symbol_alloc_arena_size = 360*K |
144 // if CDS give symbol table a default arena size since most symbols | 154 // if CDS give symbol table a default arena size since most symbols |
145 // are already allocated in the shared misc section. | 155 // are already allocated in the shared misc section. |
146 initialize_symbols(); | 156 initialize_symbols(); |
147 } | 157 } |
148 | 158 |
159 static unsigned int hash_symbol(const char* s, int len, unsigned int hashValue = 0); | |
160 | |
149 static Symbol* lookup(const char* name, int len, TRAPS); | 161 static Symbol* lookup(const char* name, int len, TRAPS); |
150 // lookup only, won't add. Also calculate hash. | 162 // lookup only, won't add. Also calculate hash. |
151 static Symbol* lookup_only(const char* name, int len, unsigned int& hash); | 163 static Symbol* lookup_only(const char* name, int len, unsigned int& hash); |
152 // Only copy to C string to be added if lookup failed. | 164 // Only copy to C string to be added if lookup failed. |
153 static Symbol* lookup(const Symbol* sym, int begin, int end, TRAPS); | 165 static Symbol* lookup(const Symbol* sym, int begin, int end, TRAPS); |
206 static void print_histogram() PRODUCT_RETURN; | 218 static void print_histogram() PRODUCT_RETURN; |
207 static void print() PRODUCT_RETURN; | 219 static void print() PRODUCT_RETURN; |
208 | 220 |
209 // Debugging | 221 // Debugging |
210 static void verify(); | 222 static void verify(); |
223 static void dump(outputStream* st); | |
211 | 224 |
212 // Sharing | 225 // Sharing |
213 static void copy_buckets(char** top, char*end) { | 226 static void copy_buckets(char** top, char*end) { |
214 the_table()->Hashtable<Symbol*>::copy_buckets(top, end); | 227 the_table()->Hashtable<Symbol*>::copy_buckets(top, end); |
215 } | 228 } |
217 the_table()->Hashtable<Symbol*>::copy_table(top, end); | 230 the_table()->Hashtable<Symbol*>::copy_table(top, end); |
218 } | 231 } |
219 static void reverse(void* boundary = NULL) { | 232 static void reverse(void* boundary = NULL) { |
220 the_table()->Hashtable<Symbol*>::reverse(boundary); | 233 the_table()->Hashtable<Symbol*>::reverse(boundary); |
221 } | 234 } |
235 | |
236 // Rehash the symbol table if it gets out of balance | |
237 static void rehash_table(); | |
238 static bool needs_rehashing() { return _needs_rehashing; } | |
222 }; | 239 }; |
240 | |
223 | 241 |
224 class StringTable : public Hashtable<oop> { | 242 class StringTable : public Hashtable<oop> { |
225 friend class VMStructs; | 243 friend class VMStructs; |
226 | 244 |
227 private: | 245 private: |
228 // The string table | 246 // The string table |
229 static StringTable* _the_table; | 247 static StringTable* _the_table; |
230 | 248 |
249 // Set if one bucket is out of balance due to hash algorithm deficiency | |
250 static bool _needs_rehashing; | |
251 static jint _seed; | |
252 | |
231 static oop intern(Handle string_or_null, jchar* chars, int length, TRAPS); | 253 static oop intern(Handle string_or_null, jchar* chars, int length, TRAPS); |
232 oop basic_add(int index, Handle string_or_null, jchar* name, int len, | 254 oop basic_add(int index, Handle string_or_null, jchar* name, int len, |
233 unsigned int hashValue, TRAPS); | 255 unsigned int hashValue, TRAPS); |
234 | 256 |
235 oop lookup(int index, jchar* chars, int length, unsigned int hashValue); | 257 oop lookup(int index, jchar* chars, int length, unsigned int hashValue); |
239 | 261 |
240 StringTable(HashtableBucket* t, int number_of_entries) | 262 StringTable(HashtableBucket* t, int number_of_entries) |
241 : Hashtable<oop>((int)StringTableSize, sizeof (HashtableEntry<oop>), t, | 263 : Hashtable<oop>((int)StringTableSize, sizeof (HashtableEntry<oop>), t, |
242 number_of_entries) {} | 264 number_of_entries) {} |
243 | 265 |
266 static bool use_alternate_hashcode() { return _seed != 0; } | |
267 static jint seed() { return _seed; } | |
268 | |
269 unsigned int new_hash(oop s); | |
244 public: | 270 public: |
245 // The string table | 271 // The string table |
246 static StringTable* the_table() { return _the_table; } | 272 static StringTable* the_table() { return _the_table; } |
247 | 273 |
248 static void create_table() { | 274 static void create_table() { |
263 static void unlink(BoolObjectClosure* cl); | 289 static void unlink(BoolObjectClosure* cl); |
264 | 290 |
265 // Invoke "f->do_oop" on the locations of all oops in the table. | 291 // Invoke "f->do_oop" on the locations of all oops in the table. |
266 static void oops_do(OopClosure* f); | 292 static void oops_do(OopClosure* f); |
267 | 293 |
294 // Hashing algorithm, used as the hash value used by the | |
295 // StringTable for bucket selection and comparison (stored in the | |
296 // HashtableEntry structures). This is used in the String.intern() method. | |
297 static unsigned int hash_string(const jchar* s, int len, unsigned int hashValue = 0); | |
298 | |
299 // Internal test. | |
300 static void test_alt_hash() PRODUCT_RETURN; | |
301 | |
268 // Probing | 302 // Probing |
269 static oop lookup(Symbol* symbol); | 303 static oop lookup(Symbol* symbol); |
270 | 304 |
271 // Interning | 305 // Interning |
272 static oop intern(Symbol* symbol, TRAPS); | 306 static oop intern(Symbol* symbol, TRAPS); |
273 static oop intern(oop string, TRAPS); | 307 static oop intern(oop string, TRAPS); |
274 static oop intern(const char *utf8_string, TRAPS); | 308 static oop intern(const char *utf8_string, TRAPS); |
275 | 309 |
276 // Debugging | 310 // Debugging |
277 static void verify(); | 311 static void verify(); |
312 static void dump(outputStream* st); | |
278 | 313 |
279 // Sharing | 314 // Sharing |
280 static void copy_buckets(char** top, char*end) { | 315 static void copy_buckets(char** top, char*end) { |
281 the_table()->Hashtable<oop>::copy_buckets(top, end); | 316 the_table()->Hashtable<oop>::copy_buckets(top, end); |
282 } | 317 } |
284 the_table()->Hashtable<oop>::copy_table(top, end); | 319 the_table()->Hashtable<oop>::copy_table(top, end); |
285 } | 320 } |
286 static void reverse() { | 321 static void reverse() { |
287 the_table()->Hashtable<oop>::reverse(); | 322 the_table()->Hashtable<oop>::reverse(); |
288 } | 323 } |
324 | |
325 // Rehash the symbol table if it gets out of balance | |
326 static void rehash_table(); | |
327 static bool needs_rehashing() { return _needs_rehashing; } | |
289 }; | 328 }; |
290 | |
291 #endif // SHARE_VM_CLASSFILE_SYMBOLTABLE_HPP | 329 #endif // SHARE_VM_CLASSFILE_SYMBOLTABLE_HPP |