thread.h

   1 // Copyright 2006 David Hilvert <dhilvert@auricle.dyndns.org>,
   2 //                              <dhilvert@ugcs.caltech.edu>
   3 //                              <dhilvert@gmail.com>
   4
   5 /*  This file is part of the Anti-Lamenessing Engine.
   6
   7     The Anti-Lamenessing Engine is free software; you can redistribute it and/or modify
   8     it under the terms of the GNU General Public License as published by
   9     the Free Software Foundation; either version 2 of the License, or
  10     (at your option) any later version.
  11
  12     The Anti-Lamenessing Engine is distributed in the hope that it will be useful,
  13     but WITHOUT ANY WARRANTY; without even the implied warranty of
  14     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15     GNU General Public License for more details.
  16
  17     You should have received a copy of the GNU General Public License
  18     along with the Anti-Lamenessing Engine; if not, write to the Free Software
  19     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20 */
  21
  22 /*
  23  * thread.h: threading details.
  24  */
  25
  26 #ifndef __thread_h__
  27 #define __thread_h__
  28
  29 #include <assert.h>
  30 #include <stdio.h>
  31 #include <string.h>
  32 #include <stdlib.h>
  33
  34 #define THREAD_PER_CPU_DEFAULT 1
  35 #define THREAD_COUNT_DEFAULT 4
  36
  37 class thread {
  38         static unsigned int _count;
  39         static unsigned int _cpu_count;
  40
  41         static void try_linux() {
  42                 assert (_cpu_count == 0);
  43
  44                 FILE *cpuinfo;
  45                 char buffer[100];
  46
  47                 cpuinfo = fopen("/proc/cpuinfo", "r");
  48
  49                 if (!cpuinfo)
  50                         return;
  51
  52                 while (!feof(cpuinfo)) {
  53                         fgets(buffer, 100, cpuinfo);
  54                         if (strncmp("processor", buffer, strlen("processor")))
  55                                 continue;
  56                         _cpu_count++;
  57                 }
  58         }
  59
  60 public:
  61         static void init() {
  62                 if (_cpu_count == 0) {
  63                         try_linux();
  64                 }
  65
  66                 if (_cpu_count > 0) {
  67                         _count = THREAD_PER_CPU_DEFAULT * _cpu_count;
  68                 } else {
  69                         fprintf(stderr, "\n\n");
  70                         fprintf(stderr, "Warning: Unable to determine CPU count.\n");
  71                         fprintf(stderr, "\n\n");
  72                         _count = THREAD_COUNT_DEFAULT;
  73                 }
  74
  75                 assert (_count > 0);
  76         }
  77
  78         static void set_per_cpu(unsigned int new_per_cpu) {
  79                 if (_cpu_count == 0) {
  80                         fprintf(stderr, "\n\n");
  81                         fprintf(stderr, "Error: per-cpu thread count specified, but CPU count is unknown.\n");
  82                         fprintf(stderr, "       Try setting the thread count explicitly.\n");
  83
  84                         exit(1);
  85                 }
  86                 if (new_per_cpu == 0) {
  87                         fprintf(stderr, "\n\n");
  88                         fprintf(stderr, "Error: per-cpu thread count specified is zero.\n");
  89                         fprintf(stderr, "       Try setting a positive thread count.\n");
  90
  91                         exit(1);
  92                 }
  93
  94                 _count = _cpu_count * new_per_cpu;
  95                 assert (_count > 0);
  96         }
  97
  98         static void set_count(unsigned int new_count) {
  99                 if (new_count == 0) {
 100                         fprintf(stderr, "\n\n");
 101                         fprintf(stderr, "Error: thread count specified is zero.\n");
 102                         fprintf(stderr, "       Try setting a positive thread count.\n");
 103
 104                         exit(1);
 105                 }
 106
 107                 _count = new_count;
 108                 assert (_count > 0);
 109         }
 110
 111         static int count() {
 112                 assert (_count > 0);
 113                 return _count;
 114         }
 115 };
 116
 117 #endif