src/cpu/sparc/vm/vm_version_sparc.cpp

Tue, 02 Nov 2010 09:00:37 -0700

author
kvn
date
Tue, 02 Nov 2010 09:00:37 -0700
changeset 2269
ae065c367d93
parent 2085
f55c4f82ab9d
child 2314
f95d63e2154a
permissions
-rw-r--r--

6987135: Performance regression on Intel platform with 32-bits edition between 6u13 and 6u14.
Summary: Use hardware DIV instruction for long division by constant when it is faster than code with multiply.
Reviewed-by: never

     1 /*
     2  * Copyright (c) 1997, 2010, 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  */
    25 # include "incls/_precompiled.incl"
    26 # include "incls/_vm_version_sparc.cpp.incl"
    28 int VM_Version::_features = VM_Version::unknown_m;
    29 const char* VM_Version::_features_str = "";
    31 bool VM_Version::is_niagara1_plus() {
    32   // This is a placeholder until the real test is determined.
    33   return is_niagara1() &&
    34     (os::processor_count() > maximum_niagara1_processor_count());
    35 }
    37 void VM_Version::initialize() {
    38   _features = determine_features();
    39   PrefetchCopyIntervalInBytes = prefetch_copy_interval_in_bytes();
    40   PrefetchScanIntervalInBytes = prefetch_scan_interval_in_bytes();
    41   PrefetchFieldsAhead         = prefetch_fields_ahead();
    43   // Allocation prefetch settings
    44   intx cache_line_size = L1_data_cache_line_size();
    45   if( cache_line_size > AllocatePrefetchStepSize )
    46     AllocatePrefetchStepSize = cache_line_size;
    47   if( FLAG_IS_DEFAULT(AllocatePrefetchLines) )
    48     AllocatePrefetchLines = 3; // Optimistic value
    49   assert( AllocatePrefetchLines > 0, "invalid value");
    50   if( AllocatePrefetchLines < 1 ) // set valid value in product VM
    51     AllocatePrefetchLines = 1; // Conservative value
    53   AllocatePrefetchDistance = allocate_prefetch_distance();
    54   AllocatePrefetchStyle    = allocate_prefetch_style();
    56   assert(AllocatePrefetchDistance % AllocatePrefetchStepSize == 0, "invalid value");
    58   UseSSE = 0; // Only on x86 and x64
    60   _supports_cx8               = has_v9();
    62   if (is_niagara1()) {
    63     // Indirect branch is the same cost as direct
    64     if (FLAG_IS_DEFAULT(UseInlineCaches)) {
    65       FLAG_SET_DEFAULT(UseInlineCaches, false);
    66     }
    67 #ifdef _LP64
    68     // 32-bit oops don't make sense for the 64-bit VM on sparc
    69     // since the 32-bit VM has the same registers and smaller objects.
    70     Universe::set_narrow_oop_shift(LogMinObjAlignmentInBytes);
    71 #endif // _LP64
    72 #ifdef COMPILER2
    73     // Indirect branch is the same cost as direct
    74     if (FLAG_IS_DEFAULT(UseJumpTables)) {
    75       FLAG_SET_DEFAULT(UseJumpTables, true);
    76     }
    77     // Single-issue, so entry and loop tops are
    78     // aligned on a single instruction boundary
    79     if (FLAG_IS_DEFAULT(InteriorEntryAlignment)) {
    80       FLAG_SET_DEFAULT(InteriorEntryAlignment, 4);
    81     }
    82     if (is_niagara1_plus()) {
    83       if (has_blk_init() && AllocatePrefetchStyle > 0 &&
    84           FLAG_IS_DEFAULT(AllocatePrefetchStyle)) {
    85         // Use BIS instruction for allocation prefetch.
    86         FLAG_SET_DEFAULT(AllocatePrefetchStyle, 3);
    87         if (FLAG_IS_DEFAULT(AllocatePrefetchDistance)) {
    88           // Use smaller prefetch distance on N2 with BIS
    89           FLAG_SET_DEFAULT(AllocatePrefetchDistance, 64);
    90         }
    91       }
    92       if (AllocatePrefetchStyle != 3 && FLAG_IS_DEFAULT(AllocatePrefetchDistance)) {
    93         // Use different prefetch distance without BIS
    94         FLAG_SET_DEFAULT(AllocatePrefetchDistance, 256);
    95       }
    96     }
    97 #endif
    98     if (FLAG_IS_DEFAULT(OptoLoopAlignment)) {
    99       FLAG_SET_DEFAULT(OptoLoopAlignment, 4);
   100     }
   101     // When using CMS, we cannot use memset() in BOT updates because
   102     // the sun4v/CMT version in libc_psr uses BIS which exposes
   103     // "phantom zeros" to concurrent readers. See 6948537.
   104     if (FLAG_IS_DEFAULT(UseMemSetInBOT) && UseConcMarkSweepGC) {
   105       FLAG_SET_DEFAULT(UseMemSetInBOT, false);
   106     }
   107   }
   109   // Use hardware population count instruction if available.
   110   if (has_hardware_popc()) {
   111     if (FLAG_IS_DEFAULT(UsePopCountInstruction)) {
   112       FLAG_SET_DEFAULT(UsePopCountInstruction, true);
   113     }
   114   }
   116 #ifdef COMPILER2
   117   // Currently not supported anywhere.
   118   FLAG_SET_DEFAULT(UseFPUForSpilling, false);
   119 #endif
   121   char buf[512];
   122   jio_snprintf(buf, sizeof(buf), "%s%s%s%s%s%s%s%s%s%s%s%s%s%s",
   123                (has_v8() ? ", has_v8" : ""),
   124                (has_v9() ? ", has_v9" : ""),
   125                (has_hardware_popc() ? ", popc" : ""),
   126                (has_vis1() ? ", has_vis1" : ""),
   127                (has_vis2() ? ", has_vis2" : ""),
   128                (has_blk_init() ? ", has_blk_init" : ""),
   129                (is_ultra3() ? ", is_ultra3" : ""),
   130                (is_sun4v() ? ", is_sun4v" : ""),
   131                (is_niagara1() ? ", is_niagara1" : ""),
   132                (is_niagara1_plus() ? ", is_niagara1_plus" : ""),
   133                (is_sparc64() ? ", is_sparc64" : ""),
   134                (!has_hardware_mul32() ? ", no-mul32" : ""),
   135                (!has_hardware_div32() ? ", no-div32" : ""),
   136                (!has_hardware_fsmuld() ? ", no-fsmuld" : ""));
   138   // buf is started with ", " or is empty
   139   _features_str = strdup(strlen(buf) > 2 ? buf + 2 : buf);
   141 #ifndef PRODUCT
   142   if (PrintMiscellaneous && Verbose) {
   143     tty->print("Allocation: ");
   144     if (AllocatePrefetchStyle <= 0) {
   145       tty->print_cr("no prefetching");
   146     } else {
   147       if (AllocatePrefetchLines > 1) {
   148         tty->print_cr("PREFETCH %d, %d lines of size %d bytes", AllocatePrefetchDistance, AllocatePrefetchLines, AllocatePrefetchStepSize);
   149       } else {
   150         tty->print_cr("PREFETCH %d, one line", AllocatePrefetchDistance);
   151       }
   152     }
   153     if (PrefetchCopyIntervalInBytes > 0) {
   154       tty->print_cr("PrefetchCopyIntervalInBytes %d", PrefetchCopyIntervalInBytes);
   155     }
   156     if (PrefetchScanIntervalInBytes > 0) {
   157       tty->print_cr("PrefetchScanIntervalInBytes %d", PrefetchScanIntervalInBytes);
   158     }
   159     if (PrefetchFieldsAhead > 0) {
   160       tty->print_cr("PrefetchFieldsAhead %d", PrefetchFieldsAhead);
   161     }
   162   }
   163 #endif // PRODUCT
   164 }
   166 void VM_Version::print_features() {
   167   tty->print_cr("Version:%s", cpu_features());
   168 }
   170 int VM_Version::determine_features() {
   171   if (UseV8InstrsOnly) {
   172     NOT_PRODUCT(if (PrintMiscellaneous && Verbose) tty->print_cr("Version is Forced-V8");)
   173     return generic_v8_m;
   174   }
   176   int features = platform_features(unknown_m); // platform_features() is os_arch specific
   178   if (features == unknown_m) {
   179     features = generic_v9_m;
   180     warning("Cannot recognize SPARC version. Default to V9");
   181   }
   183   if (UseNiagaraInstrs) {
   184     if (is_niagara1(features)) {
   185       // Happy to accomodate...
   186     } else {
   187       NOT_PRODUCT(if (PrintMiscellaneous && Verbose) tty->print_cr("Version is Forced-Niagara");)
   188       features = niagara1_m;
   189     }
   190   } else {
   191     if (is_niagara1(features) && !FLAG_IS_DEFAULT(UseNiagaraInstrs)) {
   192       NOT_PRODUCT(if (PrintMiscellaneous && Verbose) tty->print_cr("Version is Forced-Not-Niagara");)
   193       features &= ~niagara1_unique_m;
   194     } else {
   195       // Happy to accomodate...
   196     }
   197   }
   199   return features;
   200 }
   202 static int saved_features = 0;
   204 void VM_Version::allow_all() {
   205   saved_features = _features;
   206   _features      = all_features_m;
   207 }
   209 void VM_Version::revert() {
   210   _features = saved_features;
   211 }
   213 unsigned int VM_Version::calc_parallel_worker_threads() {
   214   unsigned int result;
   215   if (is_niagara1_plus()) {
   216     result = nof_parallel_worker_threads(5, 16, 8);
   217   } else {
   218     result = nof_parallel_worker_threads(5, 8, 8);
   219   }
   220   return result;
   221 }

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