1 /*
   2  * Copyright (c) 1997, 2011, 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 #ifndef SHARE_VM_RUNTIME_VM_VERSION_HPP
  26 #define SHARE_VM_RUNTIME_VM_VERSION_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 #include "utilities/ostream.hpp"
  30 
  31 // VM_Version provides information about the VM.
  32 
  33 class Abstract_VM_Version: AllStatic {
  34  protected:
  35   friend class VMStructs;
  36   static const char*  _s_vm_release;
  37   static const char*  _s_internal_vm_info_string;
  38   // These are set by machine-dependent initializations
  39   static bool         _supports_cx8;
  40   static unsigned int _logical_processors_per_package;
  41   static int          _vm_major_version;
  42   static int          _vm_minor_version;
  43   static int          _vm_build_number;
  44   static bool         _initialized;
  45   static int          _parallel_worker_threads;
  46   static bool         _parallel_worker_threads_initialized;
  47   static int          _reserve_for_allocation_prefetch;
  48 
  49   static unsigned int nof_parallel_worker_threads(unsigned int num,
  50                                                   unsigned int dem,
  51                                                   unsigned int switch_pt);
  52  public:
  53   static void initialize();
  54 
  55   // Name
  56   static const char* vm_name();
  57   // Vendor
  58   static const char* vm_vendor();
  59   // VM version information string printed by launcher (java -version)
  60   static const char* vm_info_string();
  61   static const char* vm_release();
  62   static const char* vm_platform_string();
  63   static const char* vm_build_user();
  64 
  65   static int vm_major_version()               { assert(_initialized, "not initialized"); return _vm_major_version; }
  66   static int vm_minor_version()               { assert(_initialized, "not initialized"); return _vm_minor_version; }
  67   static int vm_build_number()                { assert(_initialized, "not initialized"); return _vm_build_number; }
  68 
  69   // Gets the jvm_version_info.jvm_version defined in jvm.h
  70   static unsigned int jvm_version();
  71 
  72   // Internal version providing additional build information
  73   static const char* internal_vm_info_string();
  74   static const char* jre_release_version();
  75 
  76   // does HW support an 8-byte compare-exchange operation?
  77   static bool supports_cx8()  {return _supports_cx8;}
  78   static unsigned int logical_processors_per_package() {
  79     return _logical_processors_per_package;
  80   }
  81 
  82   // Need a space at the end of TLAB for prefetch instructions
  83   // which may fault when accessing memory outside of heap.
  84   static int reserve_for_allocation_prefetch() {
  85     return _reserve_for_allocation_prefetch;
  86   }
  87 
  88   // ARCH specific policy for the BiasedLocking
  89   static bool use_biased_locking()  { return true; }
  90 
  91   // Number of page sizes efficiently supported by the hardware.  Most chips now
  92   // support two sizes, thus this default implementation.  Processor-specific
  93   // subclasses should define new versions to hide this one as needed.  Note
  94   // that the O/S may support more sizes, but at most this many are used.
  95   static uint page_size_count() { return 2; }
  96 
  97   // Returns the number of parallel threads to be used for VM
  98   // work.  If that number has not been calculated, do so and
  99   // save it.  Returns ParallelGCThreads if it is set on the
 100   // command line.
 101   static unsigned int parallel_worker_threads();
 102   // Calculates and returns the number of parallel threads.  May
 103   // be VM version specific.
 104   static unsigned int calc_parallel_worker_threads();
 105 };
 106 
 107 #endif // SHARE_VM_RUNTIME_VM_VERSION_HPP