jdk8-mips64-public/hotspot: src/cpu/x86/vm/vm_version

src/cpu/x86/vm/vm_version_x86.hpp@f0c2369fda5a (annotated)

src/cpu/x86/vm/vm_version_x86.hpp

Thu, 06 Dec 2012 09:57:41 -0800

author: twisti
date: Thu, 06 Dec 2012 09:57:41 -0800
changeset 4323: f0c2369fda5a
parent 4205: a3ecd773a7b9
child 4410: 00af3a3a8df4
permissions: -rw-r--r--

8003250: SPARC: move MacroAssembler into separate file
Reviewed-by: jrose, kvn

 /*
  * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code 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 General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */
 #ifndef CPU_X86_VM_VM_VERSION_X86_HPP
 #define CPU_X86_VM_VM_VERSION_X86_HPP
 #include "runtime/globals_extension.hpp"
 #include "runtime/vm_version.hpp"
 class VM_Version : public Abstract_VM_Version {
 public:
   // cpuid result register layouts.  These are all unions of a uint32_t
   // (in case anyone wants access to the register as a whole) and a bitfield.
   union StdCpuid1Eax {
     uint32_t value;
     struct {
       uint32_t stepping   : 4,
                model      : 4,
                family     : 4,
                proc_type  : 2,
                           : 2,
                ext_model  : 4,
                ext_family : 8,
                           : 4;
     } bits;
   };
   union StdCpuid1Ebx { // example, unused
     uint32_t value;
     struct {
       uint32_t brand_id         : 8,
                clflush_size     : 8,
                threads_per_cpu  : 8,
                apic_id          : 8;
     } bits;
   };
   union StdCpuid1Ecx {
     uint32_t value;
     struct {
       uint32_t sse3     : 1,
                         : 2,
                monitor  : 1,
                         : 1,
                vmx      : 1,
                         : 1,
                est      : 1,
                         : 1,
                ssse3    : 1,
                cid      : 1,
                         : 2,
                cmpxchg16: 1,
                         : 4,
                dca      : 1,
                sse4_1   : 1,
                sse4_2   : 1,
                         : 2,
                popcnt   : 1,
                         : 1,
                aes      : 1,
                         : 1,
                osxsave  : 1,
                avx      : 1,
                         : 3;
     } bits;
   };
   union StdCpuid1Edx {
     uint32_t value;
     struct {
       uint32_t          : 4,
                tsc      : 1,
                         : 3,
                cmpxchg8 : 1,
                         : 6,
                cmov     : 1,
                         : 3,
                clflush  : 1,
                         : 3,
                mmx      : 1,
                fxsr     : 1,
                sse      : 1,
                sse2     : 1,
                         : 1,
                ht       : 1,
                         : 3;
     } bits;
   };
   union DcpCpuid4Eax {
     uint32_t value;
     struct {
       uint32_t cache_type    : 5,
                              : 21,
                cores_per_cpu : 6;
     } bits;
   };
   union DcpCpuid4Ebx {
     uint32_t value;
     struct {
       uint32_t L1_line_size  : 12,
                partitions    : 10,
                associativity : 10;
     } bits;
   };
   union TplCpuidBEbx {
     uint32_t value;
     struct {
       uint32_t logical_cpus : 16,
                             : 16;
     } bits;
   };
   union ExtCpuid1Ecx {
     uint32_t value;
     struct {
       uint32_t LahfSahf     : 1,
                CmpLegacy    : 1,
                             : 4,
                lzcnt        : 1,
                sse4a        : 1,
                misalignsse  : 1,
                prefetchw    : 1,
                             : 22;
     } bits;
   };
   union ExtCpuid1Edx {
     uint32_t value;
     struct {
       uint32_t           : 22,
                mmx_amd   : 1,
                mmx       : 1,
                fxsr      : 1,
                          : 4,
                long_mode : 1,
                tdnow2    : 1,
                tdnow     : 1;
     } bits;
   };
   union ExtCpuid5Ex {
     uint32_t value;
     struct {
       uint32_t L1_line_size : 8,
                L1_tag_lines : 8,
                L1_assoc     : 8,
                L1_size      : 8;
     } bits;
   };
   union ExtCpuid7Edx {
     uint32_t value;
     struct {
       uint32_t               : 8,
               tsc_invariance : 1,
                              : 23;
     } bits;
   };
   union ExtCpuid8Ecx {
     uint32_t value;
     struct {
       uint32_t cores_per_cpu : 8,
                              : 24;
     } bits;
   };
   union SefCpuid7Eax {
     uint32_t value;
   };
   union SefCpuid7Ebx {
     uint32_t value;
     struct {
       uint32_t fsgsbase : 1,
                         : 2,
                    bmi1 : 1,
                         : 1,
                    avx2 : 1,
                         : 2,
                    bmi2 : 1,
                         : 23;
     } bits;
   };
   union XemXcr0Eax {
     uint32_t value;
     struct {
       uint32_t x87 : 1,
                sse : 1,
                ymm : 1,
                    : 29;
     } bits;
   };
 protected:
   static int _cpu;
   static int _model;
   static int _stepping;
   static int _cpuFeatures;     // features returned by the "cpuid" instruction
                                // 0 if this instruction is not available
   static const char* _features_str;
   enum {
     CPU_CX8    = (1 << 0), // next bits are from cpuid 1 (EDX)
     CPU_CMOV   = (1 << 1),
     CPU_FXSR   = (1 << 2),
     CPU_HT     = (1 << 3),
     CPU_MMX    = (1 << 4),
     CPU_3DNOW_PREFETCH  = (1 << 5), // Processor supports 3dnow prefetch and prefetchw instructions
                                     // may not necessarily support other 3dnow instructions
     CPU_SSE    = (1 << 6),
     CPU_SSE2   = (1 << 7),
     CPU_SSE3   = (1 << 8), // SSE3 comes from cpuid 1 (ECX)
     CPU_SSSE3  = (1 << 9),
     CPU_SSE4A  = (1 << 10),
     CPU_SSE4_1 = (1 << 11),
     CPU_SSE4_2 = (1 << 12),
     CPU_POPCNT = (1 << 13),
     CPU_LZCNT  = (1 << 14),
     CPU_TSC    = (1 << 15),
     CPU_TSCINV = (1 << 16),
     CPU_AVX    = (1 << 17),
     CPU_AVX2   = (1 << 18),
     CPU_AES    = (1 << 19)
   } cpuFeatureFlags;
   enum {
     // AMD
     CPU_FAMILY_AMD_11H       = 0x11,
     // Intel
     CPU_FAMILY_INTEL_CORE    = 6,
     CPU_MODEL_NEHALEM        = 0x1e,
     CPU_MODEL_NEHALEM_EP     = 0x1a,
     CPU_MODEL_NEHALEM_EX     = 0x2e,
     CPU_MODEL_WESTMERE       = 0x25,
     CPU_MODEL_WESTMERE_EP    = 0x2c,
     CPU_MODEL_WESTMERE_EX    = 0x2f,
     CPU_MODEL_SANDYBRIDGE    = 0x2a,
     CPU_MODEL_SANDYBRIDGE_EP = 0x2d,
     CPU_MODEL_IVYBRIDGE_EP   = 0x3a
   } cpuExtendedFamily;
   // cpuid information block.  All info derived from executing cpuid with
   // various function numbers is stored here.  Intel and AMD info is
   // merged in this block: accessor methods disentangle it.
   //
   // The info block is laid out in subblocks of 4 dwords corresponding to
   // eax, ebx, ecx and edx, whether or not they contain anything useful.
   struct CpuidInfo {
     // cpuid function 0
     uint32_t std_max_function;
     uint32_t std_vendor_name_0;
     uint32_t std_vendor_name_1;
     uint32_t std_vendor_name_2;
     // cpuid function 1
     StdCpuid1Eax std_cpuid1_eax;
     StdCpuid1Ebx std_cpuid1_ebx;
     StdCpuid1Ecx std_cpuid1_ecx;
     StdCpuid1Edx std_cpuid1_edx;
     // cpuid function 4 (deterministic cache parameters)
     DcpCpuid4Eax dcp_cpuid4_eax;
     DcpCpuid4Ebx dcp_cpuid4_ebx;
     uint32_t     dcp_cpuid4_ecx; // unused currently
     uint32_t     dcp_cpuid4_edx; // unused currently
     // cpuid function 7 (structured extended features)
     SefCpuid7Eax sef_cpuid7_eax;
     SefCpuid7Ebx sef_cpuid7_ebx;
     uint32_t     sef_cpuid7_ecx; // unused currently
     uint32_t     sef_cpuid7_edx; // unused currently
     // cpuid function 0xB (processor topology)
     // ecx = 0
     uint32_t     tpl_cpuidB0_eax;
     TplCpuidBEbx tpl_cpuidB0_ebx;
     uint32_t     tpl_cpuidB0_ecx; // unused currently
     uint32_t     tpl_cpuidB0_edx; // unused currently
     // ecx = 1
     uint32_t     tpl_cpuidB1_eax;
     TplCpuidBEbx tpl_cpuidB1_ebx;
     uint32_t     tpl_cpuidB1_ecx; // unused currently
     uint32_t     tpl_cpuidB1_edx; // unused currently
     // ecx = 2
     uint32_t     tpl_cpuidB2_eax;
     TplCpuidBEbx tpl_cpuidB2_ebx;
     uint32_t     tpl_cpuidB2_ecx; // unused currently
     uint32_t     tpl_cpuidB2_edx; // unused currently
     // cpuid function 0x80000000 // example, unused
     uint32_t ext_max_function;
     uint32_t ext_vendor_name_0;
     uint32_t ext_vendor_name_1;
     uint32_t ext_vendor_name_2;
     // cpuid function 0x80000001
     uint32_t     ext_cpuid1_eax; // reserved
     uint32_t     ext_cpuid1_ebx; // reserved
     ExtCpuid1Ecx ext_cpuid1_ecx;
     ExtCpuid1Edx ext_cpuid1_edx;
     // cpuid functions 0x80000002 thru 0x80000004: example, unused
     uint32_t proc_name_0, proc_name_1, proc_name_2, proc_name_3;
     uint32_t proc_name_4, proc_name_5, proc_name_6, proc_name_7;
     uint32_t proc_name_8, proc_name_9, proc_name_10,proc_name_11;
     // cpuid function 0x80000005 // AMD L1, Intel reserved
     uint32_t     ext_cpuid5_eax; // unused currently
     uint32_t     ext_cpuid5_ebx; // reserved
     ExtCpuid5Ex  ext_cpuid5_ecx; // L1 data cache info (AMD)
     ExtCpuid5Ex  ext_cpuid5_edx; // L1 instruction cache info (AMD)
     // cpuid function 0x80000007
     uint32_t     ext_cpuid7_eax; // reserved
     uint32_t     ext_cpuid7_ebx; // reserved
     uint32_t     ext_cpuid7_ecx; // reserved
     ExtCpuid7Edx ext_cpuid7_edx; // tscinv
     // cpuid function 0x80000008
     uint32_t     ext_cpuid8_eax; // unused currently
     uint32_t     ext_cpuid8_ebx; // reserved
     ExtCpuid8Ecx ext_cpuid8_ecx;
     uint32_t     ext_cpuid8_edx; // reserved
     // extended control register XCR0 (the XFEATURE_ENABLED_MASK register)
     XemXcr0Eax   xem_xcr0_eax;
     uint32_t     xem_xcr0_edx; // reserved
   };
   // The actual cpuid info block
   static CpuidInfo _cpuid_info;
   // Extractors and predicates
   static uint32_t extended_cpu_family() {
     uint32_t result = _cpuid_info.std_cpuid1_eax.bits.family;
     result += _cpuid_info.std_cpuid1_eax.bits.ext_family;
     return result;
   }
   static uint32_t extended_cpu_model() {
     uint32_t result = _cpuid_info.std_cpuid1_eax.bits.model;
     result |= _cpuid_info.std_cpuid1_eax.bits.ext_model << 4;
     return result;
   }
   static uint32_t cpu_stepping() {
     uint32_t result = _cpuid_info.std_cpuid1_eax.bits.stepping;
     return result;
   }
   static uint logical_processor_count() {
     uint result = threads_per_core();
     return result;
   }
   static uint32_t feature_flags() {
     uint32_t result = 0;
     if (_cpuid_info.std_cpuid1_edx.bits.cmpxchg8 != 0)
       result |= CPU_CX8;
     if (_cpuid_info.std_cpuid1_edx.bits.cmov != 0)
       result |= CPU_CMOV;
     if (_cpuid_info.std_cpuid1_edx.bits.fxsr != 0 || (is_amd() &&
         _cpuid_info.ext_cpuid1_edx.bits.fxsr != 0))
       result |= CPU_FXSR;
     // HT flag is set for multi-core processors also.
     if (threads_per_core() > 1)
       result |= CPU_HT;
     if (_cpuid_info.std_cpuid1_edx.bits.mmx != 0 || (is_amd() &&
         _cpuid_info.ext_cpuid1_edx.bits.mmx != 0))
       result |= CPU_MMX;
     if (_cpuid_info.std_cpuid1_edx.bits.sse != 0)
       result |= CPU_SSE;
     if (_cpuid_info.std_cpuid1_edx.bits.sse2 != 0)
       result |= CPU_SSE2;
     if (_cpuid_info.std_cpuid1_ecx.bits.sse3 != 0)
       result |= CPU_SSE3;
     if (_cpuid_info.std_cpuid1_ecx.bits.ssse3 != 0)
       result |= CPU_SSSE3;
     if (_cpuid_info.std_cpuid1_ecx.bits.sse4_1 != 0)
       result |= CPU_SSE4_1;
     if (_cpuid_info.std_cpuid1_ecx.bits.sse4_2 != 0)
       result |= CPU_SSE4_2;
     if (_cpuid_info.std_cpuid1_ecx.bits.popcnt != 0)
       result |= CPU_POPCNT;
     if (_cpuid_info.std_cpuid1_ecx.bits.avx != 0 &&
         _cpuid_info.std_cpuid1_ecx.bits.osxsave != 0 &&
         _cpuid_info.xem_xcr0_eax.bits.sse != 0 &&
         _cpuid_info.xem_xcr0_eax.bits.ymm != 0) {
       result |= CPU_AVX;
       if (_cpuid_info.sef_cpuid7_ebx.bits.avx2 != 0)
         result |= CPU_AVX2;
     }
     if (_cpuid_info.std_cpuid1_edx.bits.tsc != 0)
       result |= CPU_TSC;
     if (_cpuid_info.ext_cpuid7_edx.bits.tsc_invariance != 0)
       result |= CPU_TSCINV;
     if (_cpuid_info.std_cpuid1_ecx.bits.aes != 0)
       result |= CPU_AES;
     // AMD features.
     if (is_amd()) {
       if ((_cpuid_info.ext_cpuid1_edx.bits.tdnow != 0) ||
           (_cpuid_info.ext_cpuid1_ecx.bits.prefetchw != 0))
         result |= CPU_3DNOW_PREFETCH;
       if (_cpuid_info.ext_cpuid1_ecx.bits.lzcnt != 0)
         result |= CPU_LZCNT;
       if (_cpuid_info.ext_cpuid1_ecx.bits.sse4a != 0)
         result |= CPU_SSE4A;
     }
     return result;
   }
   static void get_processor_features();
 public:
   // Offsets for cpuid asm stub
   static ByteSize std_cpuid0_offset() { return byte_offset_of(CpuidInfo, std_max_function); }
   static ByteSize std_cpuid1_offset() { return byte_offset_of(CpuidInfo, std_cpuid1_eax); }
   static ByteSize dcp_cpuid4_offset() { return byte_offset_of(CpuidInfo, dcp_cpuid4_eax); }
   static ByteSize sef_cpuid7_offset() { return byte_offset_of(CpuidInfo, sef_cpuid7_eax); }
   static ByteSize ext_cpuid1_offset() { return byte_offset_of(CpuidInfo, ext_cpuid1_eax); }
   static ByteSize ext_cpuid5_offset() { return byte_offset_of(CpuidInfo, ext_cpuid5_eax); }
   static ByteSize ext_cpuid7_offset() { return byte_offset_of(CpuidInfo, ext_cpuid7_eax); }
   static ByteSize ext_cpuid8_offset() { return byte_offset_of(CpuidInfo, ext_cpuid8_eax); }
   static ByteSize tpl_cpuidB0_offset() { return byte_offset_of(CpuidInfo, tpl_cpuidB0_eax); }
   static ByteSize tpl_cpuidB1_offset() { return byte_offset_of(CpuidInfo, tpl_cpuidB1_eax); }
   static ByteSize tpl_cpuidB2_offset() { return byte_offset_of(CpuidInfo, tpl_cpuidB2_eax); }
   static ByteSize xem_xcr0_offset() { return byte_offset_of(CpuidInfo, xem_xcr0_eax); }
   // Initialization
   static void initialize();
   // Asserts
   static void assert_is_initialized() {
     assert(_cpuid_info.std_cpuid1_eax.bits.family != 0, "VM_Version not initialized");
   }
   //
   // Processor family:
   //       3   -  386
   //       4   -  486
   //       5   -  Pentium
   //       6   -  PentiumPro, Pentium II, Celeron, Xeon, Pentium III, Athlon,
   //              Pentium M, Core Solo, Core Duo, Core2 Duo
   //    family 6 model:   9,        13,       14,        15
   //    0x0f   -  Pentium 4, Opteron
   //
   // Note: The cpu family should be used to select between
   //       instruction sequences which are valid on all Intel
   //       processors.  Use the feature test functions below to
   //       determine whether a particular instruction is supported.
   //
   static int  cpu_family()        { return _cpu;}
   static bool is_P6()             { return cpu_family() >= 6; }
   static bool is_amd()            { assert_is_initialized(); return _cpuid_info.std_vendor_name_0 == 0x68747541; } // 'htuA'
   static bool is_intel()          { assert_is_initialized(); return _cpuid_info.std_vendor_name_0 == 0x756e6547; } // 'uneG'
   static bool supports_processor_topology() {
     return (_cpuid_info.std_max_function >= 0xB) &&
            // eax[4:0] | ebx[0:15] == 0 indicates invalid topology level.
            // Some cpus have max cpuid >= 0xB but do not support processor topology.
            ((_cpuid_info.tpl_cpuidB0_eax & 0x1f | _cpuid_info.tpl_cpuidB0_ebx.bits.logical_cpus) != 0);
   }
   static uint cores_per_cpu()  {
     uint result = 1;
     if (is_intel()) {
       if (supports_processor_topology()) {
         result = _cpuid_info.tpl_cpuidB1_ebx.bits.logical_cpus /
                  _cpuid_info.tpl_cpuidB0_ebx.bits.logical_cpus;
       } else {
         result = (_cpuid_info.dcp_cpuid4_eax.bits.cores_per_cpu + 1);
       }
     } else if (is_amd()) {
       result = (_cpuid_info.ext_cpuid8_ecx.bits.cores_per_cpu + 1);
     }
     return result;
   }
   static uint threads_per_core()  {
     uint result = 1;
     if (is_intel() && supports_processor_topology()) {
       result = _cpuid_info.tpl_cpuidB0_ebx.bits.logical_cpus;
     } else if (_cpuid_info.std_cpuid1_edx.bits.ht != 0) {
       result = _cpuid_info.std_cpuid1_ebx.bits.threads_per_cpu /
                cores_per_cpu();
     }
     return result;
   }
   static intx prefetch_data_size()  {
     intx result = 0;
     if (is_intel()) {
       result = (_cpuid_info.dcp_cpuid4_ebx.bits.L1_line_size + 1);
     } else if (is_amd()) {
       result = _cpuid_info.ext_cpuid5_ecx.bits.L1_line_size;
     }
     if (result < 32) // not defined ?
       result = 32;   // 32 bytes by default on x86 and other x64
     return result;
   }
   //
   // Feature identification
   //
   static bool supports_cpuid()    { return _cpuFeatures  != 0; }
   static bool supports_cmpxchg8() { return (_cpuFeatures & CPU_CX8) != 0; }
   static bool supports_cmov()     { return (_cpuFeatures & CPU_CMOV) != 0; }
   static bool supports_fxsr()     { return (_cpuFeatures & CPU_FXSR) != 0; }
   static bool supports_ht()       { return (_cpuFeatures & CPU_HT) != 0; }
   static bool supports_mmx()      { return (_cpuFeatures & CPU_MMX) != 0; }
   static bool supports_sse()      { return (_cpuFeatures & CPU_SSE) != 0; }
   static bool supports_sse2()     { return (_cpuFeatures & CPU_SSE2) != 0; }
   static bool supports_sse3()     { return (_cpuFeatures & CPU_SSE3) != 0; }
   static bool supports_ssse3()    { return (_cpuFeatures & CPU_SSSE3)!= 0; }
   static bool supports_sse4_1()   { return (_cpuFeatures & CPU_SSE4_1) != 0; }
   static bool supports_sse4_2()   { return (_cpuFeatures & CPU_SSE4_2) != 0; }
   static bool supports_popcnt()   { return (_cpuFeatures & CPU_POPCNT) != 0; }
   static bool supports_avx()      { return (_cpuFeatures & CPU_AVX) != 0; }
   static bool supports_avx2()     { return (_cpuFeatures & CPU_AVX2) != 0; }
   static bool supports_tsc()      { return (_cpuFeatures & CPU_TSC)    != 0; }
   static bool supports_aes()      { return (_cpuFeatures & CPU_AES) != 0; }
   // Intel features
   static bool is_intel_family_core() { return is_intel() &&
                                        extended_cpu_family() == CPU_FAMILY_INTEL_CORE; }
   static bool is_intel_tsc_synched_at_init()  {
     if (is_intel_family_core()) {
       uint32_t ext_model = extended_cpu_model();
       if (ext_model == CPU_MODEL_NEHALEM_EP     ||
           ext_model == CPU_MODEL_WESTMERE_EP    ||
           ext_model == CPU_MODEL_SANDYBRIDGE_EP ||
           ext_model == CPU_MODEL_IVYBRIDGE_EP) {
         // <= 2-socket invariant tsc support. EX versions are usually used
         // in > 2-socket systems and likely don't synchronize tscs at
         // initialization.
         // Code that uses tsc values must be prepared for them to arbitrarily
         // jump forward or backward.
         return true;
       }
     }
     return false;
   }
   // AMD features
   static bool supports_3dnow_prefetch()    { return (_cpuFeatures & CPU_3DNOW_PREFETCH) != 0; }
   static bool supports_mmx_ext()  { return is_amd() && _cpuid_info.ext_cpuid1_edx.bits.mmx_amd != 0; }
   static bool supports_lzcnt()    { return (_cpuFeatures & CPU_LZCNT) != 0; }
   static bool supports_sse4a()    { return (_cpuFeatures & CPU_SSE4A) != 0; }
   static bool is_amd_Barcelona()  { return is_amd() &&
                                            extended_cpu_family() == CPU_FAMILY_AMD_11H; }
   // Intel and AMD newer cores support fast timestamps well
   static bool supports_tscinv_bit() {
     return (_cpuFeatures & CPU_TSCINV) != 0;
   }
   static bool supports_tscinv() {
     return supports_tscinv_bit() &&
            ( (is_amd() && !is_amd_Barcelona()) ||
              is_intel_tsc_synched_at_init() );
   }
   // Intel Core and newer cpus have fast IDIV instruction (excluding Atom).
   static bool has_fast_idiv()     { return is_intel() && cpu_family() == 6 &&
                                            supports_sse3() && _model != 0x1C; }
   static bool supports_compare_and_exchange() { return true; }
   static const char* cpu_features()           { return _features_str; }
   static intx allocate_prefetch_distance() {
     // This method should be called before allocate_prefetch_style().
     //
     // Hardware prefetching (distance/size in bytes):
     // Pentium 3 -  64 /  32
     // Pentium 4 - 256 / 128
     // Athlon    -  64 /  32 ????
     // Opteron   - 128 /  64 only when 2 sequential cache lines accessed
     // Core      - 128 /  64
     //
     // Software prefetching (distance in bytes / instruction with best score):
     // Pentium 3 - 128 / prefetchnta
     // Pentium 4 - 512 / prefetchnta
     // Athlon    - 128 / prefetchnta
     // Opteron   - 256 / prefetchnta
     // Core      - 256 / prefetchnta
     // It will be used only when AllocatePrefetchStyle > 0
     intx count = AllocatePrefetchDistance;
     if (count < 0) {   // default ?
       if (is_amd()) {  // AMD
         if (supports_sse2())
           count = 256; // Opteron
         else
           count = 128; // Athlon
       } else {         // Intel
         if (supports_sse2())
           if (cpu_family() == 6) {
             count = 256; // Pentium M, Core, Core2
           } else {
             count = 512; // Pentium 4
           }
         else
           count = 128; // Pentium 3 (and all other old CPUs)
       }
     }
     return count;
   }
   static intx allocate_prefetch_style() {
     assert(AllocatePrefetchStyle >= 0, "AllocatePrefetchStyle should be positive");
     // Return 0 if AllocatePrefetchDistance was not defined.
     return AllocatePrefetchDistance > 0 ? AllocatePrefetchStyle : 0;
   }
   // Prefetch interval for gc copy/scan == 9 dcache lines.  Derived from
   // 50-warehouse specjbb runs on a 2-way 1.8ghz opteron using a 4gb heap.
   // Tested intervals from 128 to 2048 in increments of 64 == one cache line.
   // 256 bytes (4 dcache lines) was the nearest runner-up to 576.
   // gc copy/scan is disabled if prefetchw isn't supported, because
   // Prefetch::write emits an inlined prefetchw on Linux.
   // Do not use the 3dnow prefetchw instruction.  It isn't supported on em64t.
   // The used prefetcht0 instruction works for both amd64 and em64t.
   static intx prefetch_copy_interval_in_bytes() {
     intx interval = PrefetchCopyIntervalInBytes;
     return interval >= 0 ? interval : 576;
   }
   static intx prefetch_scan_interval_in_bytes() {
     intx interval = PrefetchScanIntervalInBytes;
     return interval >= 0 ? interval : 576;
   }
   static intx prefetch_fields_ahead() {
     intx count = PrefetchFieldsAhead;
     return count >= 0 ? count : 1;
   }
 };
 #endif // CPU_X86_VM_VM_VERSION_X86_HPP

Mercurial > jdk8-mips64-public > hotspot / annotate

src/cpu/x86/vm/vm_version_x86.hpp@f0c2369fda5a (annotated)

src/cpu/x86/vm/vm_version_x86.hpp