1 /* 2 * Copyright (c) 1997, 2017, 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 "jvm.h" 27 #include "asm/macroAssembler.inline.hpp" 28 #include "logging/log.hpp" 29 #include "logging/logStream.hpp" 30 #include "memory/resourceArea.hpp" 31 #include "runtime/java.hpp" 32 #include "runtime/os.hpp" 33 #include "runtime/stubCodeGenerator.hpp" 34 #include "vm_version_sparc.hpp" 35 36 #include <sys/mman.h> 37 38 uint VM_Version::_L2_data_cache_line_size = 0; 39 40 void VM_Version::initialize() { 41 assert(_features != 0, "System pre-initialization is not complete."); 42 guarantee(VM_Version::has_v9(), "only SPARC v9 is supported"); 43 44 PrefetchCopyIntervalInBytes = prefetch_copy_interval_in_bytes(); 45 PrefetchScanIntervalInBytes = prefetch_scan_interval_in_bytes(); 46 PrefetchFieldsAhead = prefetch_fields_ahead(); 47 48 // Allocation prefetch settings 49 50 AllocatePrefetchDistance = allocate_prefetch_distance(); 51 AllocatePrefetchStyle = allocate_prefetch_style(); 52 53 intx cache_line_size = prefetch_data_size(); 54 55 if (FLAG_IS_DEFAULT(AllocatePrefetchStepSize)) { 56 AllocatePrefetchStepSize = MAX2(AllocatePrefetchStepSize, cache_line_size); 57 } 58 59 if (AllocatePrefetchInstr == 1) { 60 if (!has_blk_init()) { 61 warning("BIS instructions required for AllocatePrefetchInstr 1 unavailable"); 62 FLAG_SET_DEFAULT(AllocatePrefetchInstr, 0); 63 } 64 if (cache_line_size <= 0) { 65 warning("Cache-line size must be known for AllocatePrefetchInstr 1 to work"); 66 FLAG_SET_DEFAULT(AllocatePrefetchInstr, 0); 67 } 68 } 69 70 UseSSE = false; // Only used on x86 and x64. 71 72 _supports_cx8 = true; // All SPARC V9 implementations. 73 _supports_atomic_getset4 = true; // Using the 'swap' instruction. 74 75 if (has_fast_ind_br() && FLAG_IS_DEFAULT(UseInlineCaches)) { 76 // Indirect and direct branches are cost equivalent. 77 FLAG_SET_DEFAULT(UseInlineCaches, false); 78 } 79 // Align loops on the proper instruction boundary to fill the instruction 80 // fetch buffer. 81 if (FLAG_IS_DEFAULT(OptoLoopAlignment)) { 82 FLAG_SET_DEFAULT(OptoLoopAlignment, VM_Version::insn_fetch_alignment); 83 } 84 85 // 32-bit oops don't make sense for the 64-bit VM on SPARC since the 32-bit 86 // VM has the same registers and smaller objects. 87 Universe::set_narrow_oop_shift(LogMinObjAlignmentInBytes); 88 Universe::set_narrow_klass_shift(LogKlassAlignmentInBytes); 89 90 #ifdef COMPILER2 91 if (has_fast_ind_br() && FLAG_IS_DEFAULT(UseJumpTables)) { 92 // Indirect and direct branches are cost equivalent. 93 FLAG_SET_DEFAULT(UseJumpTables, true); 94 } 95 // Entry and loop tops are aligned to fill the instruction fetch buffer. 96 if (FLAG_IS_DEFAULT(InteriorEntryAlignment)) { 97 FLAG_SET_DEFAULT(InteriorEntryAlignment, VM_Version::insn_fetch_alignment); 98 } 99 if (UseTLAB && cache_line_size > 0 && 100 FLAG_IS_DEFAULT(AllocatePrefetchInstr)) { 101 if (has_fast_bis()) { 102 // Use BIS instruction for TLAB allocation prefetch. 103 FLAG_SET_DEFAULT(AllocatePrefetchInstr, 1); 104 } 105 else if (has_sparc5()) { 106 // Use prefetch instruction to avoid partial RAW issue on Core C4 processors, 107 // also use prefetch style 3. 108 FLAG_SET_DEFAULT(AllocatePrefetchInstr, 0); 109 if (FLAG_IS_DEFAULT(AllocatePrefetchStyle)) { 110 FLAG_SET_DEFAULT(AllocatePrefetchStyle, 3); 111 } 112 } 113 } 114 if (AllocatePrefetchInstr == 1) { 115 // Use allocation prefetch style 3 because BIS instructions require 116 // aligned memory addresses. 117 FLAG_SET_DEFAULT(AllocatePrefetchStyle, 3); 118 } 119 if (FLAG_IS_DEFAULT(AllocatePrefetchDistance)) { 120 if (AllocatePrefetchInstr == 0) { 121 // Use different prefetch distance without BIS 122 FLAG_SET_DEFAULT(AllocatePrefetchDistance, 256); 123 } else { 124 // Use smaller prefetch distance with BIS 125 FLAG_SET_DEFAULT(AllocatePrefetchDistance, 64); 126 } 127 } 128 129 // We increase the number of prefetched cache lines, to use just a bit more 130 // aggressive approach, when the L2-cache line size is small (32 bytes), or 131 // when running on newer processor implementations, such as the Core C4. 132 bool inc_prefetch = cache_line_size > 0 && (cache_line_size < 64 || has_sparc5()); 133 134 if (inc_prefetch) { 135 // We use a factor two for small cache line sizes (as before) but a slightly 136 // more conservative increase when running on more recent hardware that will 137 // benefit from just a bit more aggressive prefetching. 138 if (FLAG_IS_DEFAULT(AllocatePrefetchLines)) { 139 const int ap_lns = AllocatePrefetchLines; 140 const int ap_inc = cache_line_size < 64 ? ap_lns : (ap_lns + 1) / 2; 141 FLAG_SET_ERGO(intx, AllocatePrefetchLines, ap_lns + ap_inc); 142 } 143 if (FLAG_IS_DEFAULT(AllocateInstancePrefetchLines)) { 144 const int ip_lns = AllocateInstancePrefetchLines; 145 const int ip_inc = cache_line_size < 64 ? ip_lns : (ip_lns + 1) / 2; 146 FLAG_SET_ERGO(intx, AllocateInstancePrefetchLines, ip_lns + ip_inc); 147 } 148 } 149 #endif /* COMPILER2 */ 150 151 // Use hardware population count instruction if available. 152 if (has_popc()) { 153 if (FLAG_IS_DEFAULT(UsePopCountInstruction)) { 154 FLAG_SET_DEFAULT(UsePopCountInstruction, true); 155 } 156 } else if (UsePopCountInstruction) { 157 warning("POPC instruction is not available on this CPU"); 158 FLAG_SET_DEFAULT(UsePopCountInstruction, false); 159 } 160 161 // Use compare and branch instructions if available. 162 if (has_cbcond()) { 163 if (FLAG_IS_DEFAULT(UseCBCond)) { 164 FLAG_SET_DEFAULT(UseCBCond, true); 165 } 166 } else if (UseCBCond) { 167 warning("CBCOND instruction is not available on this CPU"); 168 FLAG_SET_DEFAULT(UseCBCond, false); 169 } 170 171 // Use 'mpmul' instruction if available. 172 if (has_mpmul()) { 173 if (FLAG_IS_DEFAULT(UseMPMUL)) { 174 FLAG_SET_DEFAULT(UseMPMUL, true); 175 } 176 } else if (UseMPMUL) { 177 warning("MPMUL instruction is not available on this CPU"); 178 FLAG_SET_DEFAULT(UseMPMUL, false); 179 } 180 181 assert(BlockZeroingLowLimit > 0, "invalid value"); 182 183 if (has_blk_zeroing() && cache_line_size > 0) { 184 if (FLAG_IS_DEFAULT(UseBlockZeroing)) { 185 FLAG_SET_DEFAULT(UseBlockZeroing, true); 186 } 187 } else if (UseBlockZeroing) { 188 warning("BIS zeroing instructions are not available on this CPU"); 189 FLAG_SET_DEFAULT(UseBlockZeroing, false); 190 } 191 192 assert(BlockCopyLowLimit > 0, "invalid value"); 193 194 if (has_blk_zeroing() && cache_line_size > 0) { 195 if (FLAG_IS_DEFAULT(UseBlockCopy)) { 196 FLAG_SET_DEFAULT(UseBlockCopy, true); 197 } 198 } else if (UseBlockCopy) { 199 warning("BIS instructions are not available or expensive on this CPU"); 200 FLAG_SET_DEFAULT(UseBlockCopy, false); 201 } 202 203 #ifdef COMPILER2 204 if (has_fast_rdpc() && FLAG_IS_DEFAULT(UseRDPCForConstantTableBase)) { 205 FLAG_SET_DEFAULT(UseRDPCForConstantTableBase, true); 206 } 207 208 // Currently not supported anywhere. 209 FLAG_SET_DEFAULT(UseFPUForSpilling, false); 210 211 MaxVectorSize = 8; 212 213 assert((InteriorEntryAlignment % relocInfo::addr_unit()) == 0, "alignment is not a multiple of NOP size"); 214 #endif 215 216 assert((CodeEntryAlignment % relocInfo::addr_unit()) == 0, "alignment is not a multiple of NOP size"); 217 assert((OptoLoopAlignment % relocInfo::addr_unit()) == 0, "alignment is not a multiple of NOP size"); 218 219 char buf[512]; 220 jio_snprintf(buf, sizeof(buf), 221 "%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s" 222 "%s%s%s%s%s%s%s%s%s" "%s%s%s%s%s%s%s%s%s" 223 "%s%s%s%s%s%s%s", 224 (has_v9() ? "v9" : ""), 225 (has_popc() ? ", popc" : ""), 226 (has_vis1() ? ", vis1" : ""), 227 (has_vis2() ? ", vis2" : ""), 228 (has_blk_init() ? ", blk_init" : ""), 229 (has_fmaf() ? ", fmaf" : ""), 230 (has_hpc() ? ", hpc" : ""), 231 (has_ima() ? ", ima" : ""), 232 (has_aes() ? ", aes" : ""), 233 (has_des() ? ", des" : ""), 234 (has_kasumi() ? ", kas" : ""), 235 (has_camellia() ? ", cam" : ""), 236 (has_md5() ? ", md5" : ""), 237 (has_sha1() ? ", sha1" : ""), 238 (has_sha256() ? ", sha256" : ""), 239 (has_sha512() ? ", sha512" : ""), 240 (has_mpmul() ? ", mpmul" : ""), 241 (has_mont() ? ", mont" : ""), 242 (has_pause() ? ", pause" : ""), 243 (has_cbcond() ? ", cbcond" : ""), 244 (has_crc32c() ? ", crc32c" : ""), 245 246 (has_athena_plus() ? ", athena_plus" : ""), 247 (has_vis3b() ? ", vis3b" : ""), 248 (has_adi() ? ", adi" : ""), 249 (has_sparc5() ? ", sparc5" : ""), 250 (has_mwait() ? ", mwait" : ""), 251 (has_xmpmul() ? ", xmpmul" : ""), 252 (has_xmont() ? ", xmont" : ""), 253 (has_pause_nsec() ? ", pause_nsec" : ""), 254 (has_vamask() ? ", vamask" : ""), 255 256 (has_sparc6() ? ", sparc6" : ""), 257 (has_dictunp() ? ", dictunp" : ""), 258 (has_fpcmpshl() ? ", fpcmpshl" : ""), 259 (has_rle() ? ", rle" : ""), 260 (has_sha3() ? ", sha3" : ""), 261 (has_athena_plus2()? ", athena_plus2" : ""), 262 (has_vis3c() ? ", vis3c" : ""), 263 (has_sparc5b() ? ", sparc5b" : ""), 264 (has_mme() ? ", mme" : ""), 265 266 (has_fast_idiv() ? ", *idiv" : ""), 267 (has_fast_rdpc() ? ", *rdpc" : ""), 268 (has_fast_bis() ? ", *bis" : ""), 269 (has_fast_ld() ? ", *ld" : ""), 270 (has_fast_cmove() ? ", *cmove" : ""), 271 (has_fast_ind_br() ? ", *ind_br" : ""), 272 (has_blk_zeroing() ? ", *blk_zeroing" : "")); 273 274 assert(strlen(buf) >= 2, "must be"); 275 276 _features_string = os::strdup(buf); 277 278 log_info(os, cpu)("SPARC features detected: %s", _features_string); 279 280 // UseVIS is set to the smallest of what hardware supports and what the command 281 // line requires, i.e. you cannot set UseVIS to 3 on older UltraSparc which do 282 // not support it. 283 284 if (UseVIS > 3) UseVIS = 3; 285 if (UseVIS < 0) UseVIS = 0; 286 if (!has_vis3()) // Drop to 2 if no VIS3 support 287 UseVIS = MIN2((intx)2, UseVIS); 288 if (!has_vis2()) // Drop to 1 if no VIS2 support 289 UseVIS = MIN2((intx)1, UseVIS); 290 if (!has_vis1()) // Drop to 0 if no VIS1 support 291 UseVIS = 0; 292 293 if (has_aes()) { 294 if (FLAG_IS_DEFAULT(UseAES)) { 295 FLAG_SET_DEFAULT(UseAES, true); 296 } 297 if (!UseAES) { 298 if (UseAESIntrinsics && !FLAG_IS_DEFAULT(UseAESIntrinsics)) { 299 warning("AES intrinsics require UseAES flag to be enabled. Intrinsics will be disabled."); 300 } 301 FLAG_SET_DEFAULT(UseAESIntrinsics, false); 302 } else { 303 // The AES intrinsic stubs require AES instruction support (of course) 304 // but also require VIS3 mode or higher for instructions it use. 305 if (UseVIS > 2) { 306 if (FLAG_IS_DEFAULT(UseAESIntrinsics)) { 307 FLAG_SET_DEFAULT(UseAESIntrinsics, true); 308 } 309 } else { 310 if (UseAESIntrinsics && !FLAG_IS_DEFAULT(UseAESIntrinsics)) { 311 warning("SPARC AES intrinsics require VIS3 instructions. Intrinsics will be disabled."); 312 } 313 FLAG_SET_DEFAULT(UseAESIntrinsics, false); 314 } 315 } 316 } else if (UseAES || UseAESIntrinsics) { 317 if (UseAES && !FLAG_IS_DEFAULT(UseAES)) { 318 warning("AES instructions are not available on this CPU"); 319 FLAG_SET_DEFAULT(UseAES, false); 320 } 321 if (UseAESIntrinsics && !FLAG_IS_DEFAULT(UseAESIntrinsics)) { 322 warning("AES intrinsics are not available on this CPU"); 323 FLAG_SET_DEFAULT(UseAESIntrinsics, false); 324 } 325 } 326 327 if (UseAESCTRIntrinsics) { 328 warning("AES/CTR intrinsics are not available on this CPU"); 329 FLAG_SET_DEFAULT(UseAESCTRIntrinsics, false); 330 } 331 332 // GHASH/GCM intrinsics 333 if (has_vis3() && (UseVIS > 2)) { 334 if (FLAG_IS_DEFAULT(UseGHASHIntrinsics)) { 335 UseGHASHIntrinsics = true; 336 } 337 } else if (UseGHASHIntrinsics) { 338 if (!FLAG_IS_DEFAULT(UseGHASHIntrinsics)) 339 warning("GHASH intrinsics require VIS3 instruction support. Intrinsics will be disabled"); 340 FLAG_SET_DEFAULT(UseGHASHIntrinsics, false); 341 } 342 343 if (has_fmaf()) { 344 if (FLAG_IS_DEFAULT(UseFMA)) { 345 UseFMA = true; 346 } 347 } else if (UseFMA) { 348 warning("FMA instructions are not available on this CPU"); 349 FLAG_SET_DEFAULT(UseFMA, false); 350 } 351 352 // SHA1, SHA256, and SHA512 instructions were added to SPARC at different times 353 if (has_sha1() || has_sha256() || has_sha512()) { 354 if (UseVIS > 0) { // SHA intrinsics use VIS1 instructions 355 if (FLAG_IS_DEFAULT(UseSHA)) { 356 FLAG_SET_DEFAULT(UseSHA, true); 357 } 358 } else { 359 if (UseSHA) { 360 warning("SPARC SHA intrinsics require VIS1 instruction support. Intrinsics will be disabled."); 361 FLAG_SET_DEFAULT(UseSHA, false); 362 } 363 } 364 } else if (UseSHA) { 365 warning("SHA instructions are not available on this CPU"); 366 FLAG_SET_DEFAULT(UseSHA, false); 367 } 368 369 if (UseSHA && has_sha1()) { 370 if (FLAG_IS_DEFAULT(UseSHA1Intrinsics)) { 371 FLAG_SET_DEFAULT(UseSHA1Intrinsics, true); 372 } 373 } else if (UseSHA1Intrinsics) { 374 warning("Intrinsics for SHA-1 crypto hash functions not available on this CPU."); 375 FLAG_SET_DEFAULT(UseSHA1Intrinsics, false); 376 } 377 378 if (UseSHA && has_sha256()) { 379 if (FLAG_IS_DEFAULT(UseSHA256Intrinsics)) { 380 FLAG_SET_DEFAULT(UseSHA256Intrinsics, true); 381 } 382 } else if (UseSHA256Intrinsics) { 383 warning("Intrinsics for SHA-224 and SHA-256 crypto hash functions not available on this CPU."); 384 FLAG_SET_DEFAULT(UseSHA256Intrinsics, false); 385 } 386 387 if (UseSHA && has_sha512()) { 388 if (FLAG_IS_DEFAULT(UseSHA512Intrinsics)) { 389 FLAG_SET_DEFAULT(UseSHA512Intrinsics, true); 390 } 391 } else if (UseSHA512Intrinsics) { 392 warning("Intrinsics for SHA-384 and SHA-512 crypto hash functions not available on this CPU."); 393 FLAG_SET_DEFAULT(UseSHA512Intrinsics, false); 394 } 395 396 if (!(UseSHA1Intrinsics || UseSHA256Intrinsics || UseSHA512Intrinsics)) { 397 FLAG_SET_DEFAULT(UseSHA, false); 398 } 399 400 if (has_crc32c()) { 401 if (UseVIS > 2) { // CRC32C intrinsics use VIS3 instructions 402 if (FLAG_IS_DEFAULT(UseCRC32CIntrinsics)) { 403 FLAG_SET_DEFAULT(UseCRC32CIntrinsics, true); 404 } 405 } else { 406 if (UseCRC32CIntrinsics) { 407 warning("SPARC CRC32C intrinsics require VIS3 instruction support. Intrinsics will be disabled."); 408 FLAG_SET_DEFAULT(UseCRC32CIntrinsics, false); 409 } 410 } 411 } else if (UseCRC32CIntrinsics) { 412 warning("CRC32C instruction is not available on this CPU"); 413 FLAG_SET_DEFAULT(UseCRC32CIntrinsics, false); 414 } 415 416 if (UseVIS > 2) { 417 if (FLAG_IS_DEFAULT(UseAdler32Intrinsics)) { 418 FLAG_SET_DEFAULT(UseAdler32Intrinsics, true); 419 } 420 } else if (UseAdler32Intrinsics) { 421 warning("SPARC Adler32 intrinsics require VIS3 instruction support. Intrinsics will be disabled."); 422 FLAG_SET_DEFAULT(UseAdler32Intrinsics, false); 423 } 424 425 if (UseVIS > 2) { 426 if (FLAG_IS_DEFAULT(UseCRC32Intrinsics)) { 427 FLAG_SET_DEFAULT(UseCRC32Intrinsics, true); 428 } 429 } else if (UseCRC32Intrinsics) { 430 warning("SPARC CRC32 intrinsics require VIS3 instructions support. Intrinsics will be disabled"); 431 FLAG_SET_DEFAULT(UseCRC32Intrinsics, false); 432 } 433 434 if (UseVIS > 2) { 435 if (FLAG_IS_DEFAULT(UseMultiplyToLenIntrinsic)) { 436 FLAG_SET_DEFAULT(UseMultiplyToLenIntrinsic, true); 437 } 438 } else if (UseMultiplyToLenIntrinsic) { 439 warning("SPARC multiplyToLen intrinsics require VIS3 instructions support. Intrinsics will be disabled"); 440 FLAG_SET_DEFAULT(UseMultiplyToLenIntrinsic, false); 441 } 442 443 if (UseVectorizedMismatchIntrinsic) { 444 warning("UseVectorizedMismatchIntrinsic specified, but not available on this CPU."); 445 FLAG_SET_DEFAULT(UseVectorizedMismatchIntrinsic, false); 446 } 447 448 if (FLAG_IS_DEFAULT(ContendedPaddingWidth) && 449 (cache_line_size > ContendedPaddingWidth)) 450 ContendedPaddingWidth = cache_line_size; 451 452 // This machine does not allow unaligned memory accesses 453 if (UseUnalignedAccesses) { 454 if (!FLAG_IS_DEFAULT(UseUnalignedAccesses)) 455 warning("Unaligned memory access is not available on this CPU"); 456 FLAG_SET_DEFAULT(UseUnalignedAccesses, false); 457 } 458 459 if (log_is_enabled(Info, os, cpu)) { 460 ResourceMark rm; 461 LogStream ls(Log(os, cpu)::info()); 462 outputStream* log = &ls; 463 log->print_cr("L1 data cache line size: %u", L1_data_cache_line_size()); 464 log->print_cr("L2 data cache line size: %u", L2_data_cache_line_size()); 465 log->print("Allocation"); 466 if (AllocatePrefetchStyle <= 0) { 467 log->print(": no prefetching"); 468 } else { 469 log->print(" prefetching: "); 470 if (AllocatePrefetchInstr == 0) { 471 log->print("PREFETCH"); 472 } else if (AllocatePrefetchInstr == 1) { 473 log->print("BIS"); 474 } 475 if (AllocatePrefetchLines > 1) { 476 log->print_cr(" at distance %d, %d lines of %d bytes", (int) AllocatePrefetchDistance, (int) AllocatePrefetchLines, (int) AllocatePrefetchStepSize); 477 } else { 478 log->print_cr(" at distance %d, one line of %d bytes", (int) AllocatePrefetchDistance, (int) AllocatePrefetchStepSize); 479 } 480 } 481 if (PrefetchCopyIntervalInBytes > 0) { 482 log->print_cr("PrefetchCopyIntervalInBytes %d", (int) PrefetchCopyIntervalInBytes); 483 } 484 if (PrefetchScanIntervalInBytes > 0) { 485 log->print_cr("PrefetchScanIntervalInBytes %d", (int) PrefetchScanIntervalInBytes); 486 } 487 if (PrefetchFieldsAhead > 0) { 488 log->print_cr("PrefetchFieldsAhead %d", (int) PrefetchFieldsAhead); 489 } 490 if (ContendedPaddingWidth > 0) { 491 log->print_cr("ContendedPaddingWidth %d", (int) ContendedPaddingWidth); 492 } 493 } 494 } 495 496 void VM_Version::print_features() { 497 tty->print("ISA features [0x%0" PRIx64 "]:", _features); 498 if (_features_string != NULL) { 499 tty->print(" %s", _features_string); 500 } 501 tty->cr(); 502 } 503 504 void VM_Version::determine_features() { 505 platform_features(); // platform_features() is os_arch specific. 506 507 assert(has_v9(), "must be"); 508 509 if (UseNiagaraInstrs) { // Limit code generation to Niagara. 510 _features &= niagara1_msk; 511 } 512 } 513 514 static uint64_t saved_features = 0; 515 516 void VM_Version::allow_all() { 517 saved_features = _features; 518 _features = full_feature_msk; 519 } 520 521 void VM_Version::revert() { 522 _features = saved_features; 523 } 524 525 /* Determine a suitable number of threads on this particular machine. 526 * 527 * FIXME: Simply checking the processor family is insufficient. 528 */ 529 unsigned int VM_Version::calc_parallel_worker_threads() { 530 const int num = 5; 531 const int den = is_post_niagara() ? 16 : 8; 532 const int threshold = 8; 533 534 return nof_parallel_worker_threads(num, den, threshold); 535 }