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1 /* Portions copyright (c) 2009 Nokia Corporation. All rights reserved.*/ |
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2 #undef G_DISABLE_ASSERT |
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3 #undef G_LOG_DOMAIN |
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4 |
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5 #include <errno.h> |
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6 #include <stdlib.h> |
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7 #include <stdio.h> |
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8 #include <string.h> |
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9 #include <unistd.h> |
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10 #include <sys/resource.h> |
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11 #include <sys/time.h> |
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12 #include <sys/poll.h> |
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13 |
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14 #define TRUE 1 |
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15 #define FALSE 0 |
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16 |
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17 static int n_children = 3; |
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18 static int n_active_children; |
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19 static int n_iters = 10000; |
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20 |
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21 static int write_fds[1024]; |
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22 static struct pollfd poll_fds[1024]; |
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23 |
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24 void |
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25 my_pipe (int *fds) |
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26 { |
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27 if (pipe(fds) < 0) |
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28 { |
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29 fprintf (stderr, "Cannot create pipe %s\n", strerror (errno)); |
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30 exit (1); |
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31 } |
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32 } |
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33 |
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34 int |
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35 read_all (int fd, char *buf, int len) |
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36 { |
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37 size_t bytes_read = 0; |
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38 ssize_t count; |
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39 |
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40 while (bytes_read < len) |
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41 { |
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42 count = read (fd, buf + bytes_read, len - bytes_read); |
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43 if (count < 0) |
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44 { |
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45 if (errno != EAGAIN) |
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46 return FALSE; |
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47 } |
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48 else if (count == 0) |
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49 return FALSE; |
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50 |
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51 bytes_read += count; |
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52 } |
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53 |
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54 return TRUE; |
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55 } |
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56 |
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57 int |
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58 write_all (int fd, char *buf, int len) |
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59 { |
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60 size_t bytes_written = 0; |
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61 ssize_t count; |
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62 |
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63 while (bytes_written < len) |
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64 { |
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65 count = write (fd, buf + bytes_written, len - bytes_written); |
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66 if (count < 0) |
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67 { |
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68 if (errno != EAGAIN) |
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69 return FALSE; |
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70 } |
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71 |
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72 bytes_written += count; |
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73 } |
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74 |
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75 return TRUE; |
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76 } |
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77 |
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78 void |
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79 run_child (int in_fd, int out_fd) |
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80 { |
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81 int i; |
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82 int val = 1; |
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83 |
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84 for (i = 0; i < n_iters; i++) |
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85 { |
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86 write_all (out_fd, (char *)&val, sizeof (val)); |
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87 read_all (in_fd, (char *)&val, sizeof (val)); |
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88 } |
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89 |
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90 val = 0; |
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91 write_all (out_fd, (char *)&val, sizeof (val)); |
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92 |
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93 exit (0); |
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94 } |
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95 |
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96 int |
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97 input_callback (int source, int dest) |
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98 { |
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99 int val; |
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100 |
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101 if (!read_all (source, (char *)&val, sizeof(val))) |
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102 { |
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103 fprintf (stderr,"Unexpected EOF\n"); |
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104 exit (1); |
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105 } |
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106 |
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107 if (val) |
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108 { |
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109 write_all (dest, (char *)&val, sizeof(val)); |
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110 return TRUE; |
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111 } |
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112 else |
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113 { |
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114 close (source); |
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115 close (dest); |
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116 |
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117 n_active_children--; |
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118 return FALSE; |
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119 } |
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120 } |
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121 |
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122 void |
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123 create_child (int pos) |
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124 { |
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125 int pid; |
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126 int in_fds[2]; |
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127 int out_fds[2]; |
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128 |
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129 my_pipe (in_fds); |
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130 my_pipe (out_fds); |
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131 |
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132 pid = fork (); |
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133 |
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134 if (pid > 0) /* Parent */ |
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135 { |
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136 close (in_fds[0]); |
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137 close (out_fds[1]); |
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138 |
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139 write_fds[pos] = in_fds[1]; |
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140 poll_fds[pos].fd = out_fds[0]; |
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141 poll_fds[pos].events = POLLIN; |
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142 } |
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143 else if (pid == 0) /* Child */ |
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144 { |
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145 close (in_fds[1]); |
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146 close (out_fds[0]); |
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147 |
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148 setsid (); |
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149 |
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150 run_child (in_fds[0], out_fds[1]); |
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151 } |
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152 else /* Error */ |
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153 { |
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154 fprintf (stderr,"Cannot fork: %s\n", strerror (errno)); |
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155 exit (1); |
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156 } |
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157 } |
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158 |
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159 static double |
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160 difftimeval (struct timeval *old, struct timeval *new) |
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161 { |
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162 return |
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163 (new->tv_sec - old->tv_sec) * 1000. + (new->tv_usec - old->tv_usec) / 1000; |
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164 } |
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165 |
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166 int |
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167 main (int argc, char **argv) |
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168 { |
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169 int i, j; |
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170 struct rusage old_usage; |
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171 struct rusage new_usage; |
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172 |
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173 if (argc > 1) |
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174 n_children = atoi(argv[1]); |
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175 |
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176 if (argc > 2) |
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177 n_iters = atoi(argv[2]); |
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178 |
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179 printf ("Children: %d Iters: %d\n", n_children, n_iters); |
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180 |
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181 n_active_children = n_children; |
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182 for (i = 0; i < n_children; i++) |
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183 create_child (i); |
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184 |
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185 getrusage (RUSAGE_SELF, &old_usage); |
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186 |
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187 while (n_active_children > 0) |
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188 { |
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189 int old_n_active_children = n_active_children; |
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190 |
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191 poll (poll_fds, n_active_children, -1); |
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192 |
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193 for (i=0; i<n_active_children; i++) |
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194 { |
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195 if (poll_fds[i].events & (POLLIN | POLLHUP)) |
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196 { |
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197 if (!input_callback (poll_fds[i].fd, write_fds[i])) |
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198 write_fds[i] = -1; |
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199 } |
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200 } |
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201 |
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202 if (old_n_active_children > n_active_children) |
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203 { |
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204 j = 0; |
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205 for (i=0; i<old_n_active_children; i++) |
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206 { |
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207 if (write_fds[i] != -1) |
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208 { |
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209 if (j < i) |
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210 { |
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211 poll_fds[j] = poll_fds[i]; |
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212 write_fds[j] = write_fds[i]; |
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213 } |
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214 j++; |
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215 } |
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216 } |
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217 } |
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218 } |
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219 |
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220 getrusage (RUSAGE_SELF, &new_usage); |
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221 |
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222 printf ("Elapsed user: %g\n", |
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223 difftimeval (&old_usage.ru_utime, &new_usage.ru_utime)); |
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224 printf ("Elapsed system: %g\n", |
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225 difftimeval (&old_usage.ru_stime, &new_usage.ru_stime)); |
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226 printf ("Elapsed total: %g\n", |
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227 difftimeval (&old_usage.ru_utime, &new_usage.ru_utime) + |
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228 difftimeval (&old_usage.ru_stime, &new_usage.ru_stime)); |
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229 printf ("total / iteration: %g\n", |
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230 (difftimeval (&old_usage.ru_utime, &new_usage.ru_utime) + |
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231 difftimeval (&old_usage.ru_stime, &new_usage.ru_stime)) / |
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232 (n_iters * n_children)); |
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233 |
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234 return 0; |
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235 } |
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236 |