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                         _count = THREAD_COUNT_DEFAULT;
  70                 }
  71
  72                 assert (_count > 0);
  73         }
  74
  75         static void set_per_cpu(unsigned int new_per_cpu) {
  76                 if (_cpu_count == 0) {
  77                         fprintf(stderr, "\n\n");
  78                         fprintf(stderr, "Error: per-cpu thread count specified, but CPU count is unknown.\n");
  79                         fprintf(stderr, "       Try setting the thread count explicitly.\n");
  80
  81                         exit(1);
  82                 }
  83                 if (new_per_cpu == 0) {
  84                         fprintf(stderr, "\n\n");
  85                         fprintf(stderr, "Error: --per-cpu argument must be positive\n");
  86                         fprintf(stderr, "\n");
  87
  88                         exit(1);
  89                 }
  90
  91                 _count = _cpu_count * new_per_cpu;
  92                 assert (_count > 0);
  93         }
  94
  95         static void set_count(unsigned int new_count) {
  96                 if (new_count == 0) {
  97                         fprintf(stderr, "\n\n");
  98                         fprintf(stderr, "Error: --thread argument must be positive\n");
  99                         fprintf(stderr, "\n");
 100
 101                         exit(1);
 102                 }
 103
 104                 _count = new_count;
 105                 assert (_count > 0);
 106         }
 107
 108         static int count() {
 109                 assert (_count > 0);
 110                 return _count;
 111         }
 112 };
 113
 114 #endif