1 /*

     2  * Copyright (c) 1998, 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.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 /* This file houses the common methods for VM ergonomics the platforms

    27  * are split into ergo_sparc and ergo_x86, and they could be split more

    28  * in the future if required. The following comments are not entirely

    29  * true after bifurcation of the platform specific files.

    30  */

    31 

    32 /*

    33  * The following methods (down to ServerClassMachine()) answer

    34  * the question about whether a machine is a "server-class"

    35  * machine.  A server-class machine is loosely defined as one

    36  * with 2 or more processors and 2 gigabytes or more physical

    37  * memory.  The definition of a processor is a physical package,

    38  * not a hyperthreaded chip masquerading as a multi-processor.

    39  * The definition of memory is also somewhat fuzzy, since x86

    40  * machines seem not to report all the memory in their DIMMs, we

    41  * think because of memory mapping of graphics cards, etc.

    42  *

    43  * This code is somewhat more confused with #ifdef's than we'd

    44  * like because this file is used by both Solaris and Linux

    45  * platforms, and so needs to be parameterized for SPARC and

    46  * i586 hardware.  The other Linux platforms (amd64 and ia64)

    47  * don't even ask this question, because they only come with

    48  * server JVMs.

    49  */

    50 

    51 #include "ergo.h"

    52 

    53 /* Dispatch to the platform-specific definition of "server-class" */

    54 jboolean

    55 ServerClassMachine(void) {

    56   jboolean result;

    57   switch(GetErgoPolicy()) {

    58     case NEVER_SERVER_CLASS:

    59       return JNI_FALSE;

    60     case ALWAYS_SERVER_CLASS:

    61       return JNI_TRUE;

    62     default:

    63       result = ServerClassMachineImpl();

    64       JLI_TraceLauncher("ServerClassMachine: returns default value of %s\n",

    65            (result == JNI_TRUE ? "true" : "false"));

    66       return result;

    67   }

    68 }

    69 

    70 #ifdef USE_GENERIC_ERGO

    71 /* Ask the OS how many processors there are. */

    72 static unsigned long

    73 physical_processors(void) {

    74   const unsigned long sys_processors = sysconf(_SC_NPROCESSORS_CONF);

    75   JLI_TraceLauncher("sysconf(_SC_NPROCESSORS_CONF): %lu\n", sys_processors);

    76   return sys_processors;

    77 }

    78 

    79 jboolean

    80 ServerClassMachineImpl(void) {

    81   jboolean            result            = JNI_FALSE;

    82   /* How big is a server class machine? */

    83   const unsigned long server_processors = 2UL;

    84   const uint64_t      server_memory     = 2UL * GB;

    85   const uint64_t      actual_memory     = physical_memory();

    86 

    87   /* Is this a server class machine? */

    88   if (actual_memory >= server_memory) {

    89     const unsigned long actual_processors = physical_processors();

    90     if (actual_processors >= server_processors) {

    91       result = JNI_TRUE;

    92     }

    93   }

    94   JLI_TraceLauncher("unix_" LIBARCHNAME "_ServerClassMachine: %s\n",

    95            (result == JNI_TRUE ? "JNI_TRUE" : "JNI_FALSE"));

    96   return result;

    97 }

    98 #endif

    99 

   100 /* Compute physical memory by asking the OS */

   101 uint64_t

   102 physical_memory(void) {

   103   const uint64_t pages     = (uint64_t) sysconf(_SC_PHYS_PAGES);

   104   const uint64_t page_size = (uint64_t) sysconf(_SC_PAGESIZE);

   105   const uint64_t result    = pages * page_size;

   106 # define UINT64_FORMAT "%" PRIu64

   107 

   108   JLI_TraceLauncher("pages: " UINT64_FORMAT

   109           "  page_size: " UINT64_FORMAT

   110           "  physical memory: " UINT64_FORMAT " (%.3fGB)\n",

   111            pages, page_size, result, result / (double) GB);

   112   return result;

   113 }