1 | =head1 NAME |
1 | =head1 NAME |
2 | |
2 | |
3 | AnyEvent::Fork - everything you wanted to use fork() for, but couldn't |
3 | AnyEvent::Fork - everything you wanted to use fork() for, but couldn't |
4 | |
4 | |
5 | ATTENTION, this is a very early release, and very untested. Consider it a |
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6 | technology preview. |
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7 | |
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8 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
9 | |
6 | |
10 | use AnyEvent::Fork; |
7 | use AnyEvent::Fork; |
11 | |
8 | |
12 | ################################################################## |
9 | AnyEvent::Fork |
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10 | ->new |
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11 | ->require ("MyModule") |
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12 | ->run ("MyModule::server", my $cv = AE::cv); |
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13 | |
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14 | my $fh = $cv->recv; |
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15 | |
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16 | =head1 DESCRIPTION |
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17 | |
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18 | This module allows you to create new processes, without actually forking |
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19 | them from your current process (avoiding the problems of forking), but |
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20 | preserving most of the advantages of fork. |
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21 | |
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22 | It can be used to create new worker processes or new independent |
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23 | subprocesses for short- and long-running jobs, process pools (e.g. for use |
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24 | in pre-forked servers) but also to spawn new external processes (such as |
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25 | CGI scripts from a web server), which can be faster (and more well behaved) |
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26 | than using fork+exec in big processes. |
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27 | |
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28 | Special care has been taken to make this module useful from other modules, |
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29 | while still supporting specialised environments such as L<App::Staticperl> |
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30 | or L<PAR::Packer>. |
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31 | |
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32 | =head2 WHAT THIS MODULE IS NOT |
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33 | |
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34 | This module only creates processes and lets you pass file handles and |
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35 | strings to it, and run perl code. It does not implement any kind of RPC - |
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36 | there is no back channel from the process back to you, and there is no RPC |
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37 | or message passing going on. |
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38 | |
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39 | If you need some form of RPC, you can either implement it yourself |
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40 | in whatever way you like, use some message-passing module such |
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41 | as L<AnyEvent::MP>, some pipe such as L<AnyEvent::ZeroMQ>, use |
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42 | L<AnyEvent::Handle> on both sides to send e.g. JSON or Storable messages, |
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43 | and so on. |
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44 | |
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45 | =head2 COMPARISON TO OTHER MODULES |
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46 | |
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47 | There is an abundance of modules on CPAN that do "something fork", such as |
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48 | L<Parallel::ForkManager>, L<AnyEvent::ForkManager>, L<AnyEvent::Worker> |
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49 | or L<AnyEvent::Subprocess>. There are modules that implement their own |
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50 | process management, such as L<AnyEvent::DBI>. |
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51 | |
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52 | The problems that all these modules try to solve are real, however, none |
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53 | of them (from what I have seen) tackle the very real problems of unwanted |
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54 | memory sharing, efficiency, not being able to use event processing or |
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55 | similar modules in the processes they create. |
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56 | |
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57 | This module doesn't try to replace any of them - instead it tries to solve |
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58 | the problem of creating processes with a minimum of fuss and overhead (and |
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59 | also luxury). Ideally, most of these would use AnyEvent::Fork internally, |
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60 | except they were written before AnyEvent:Fork was available, so obviously |
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61 | had to roll their own. |
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62 | |
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63 | =head2 PROBLEM STATEMENT |
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64 | |
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65 | There are two traditional ways to implement parallel processing on UNIX |
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66 | like operating systems - fork and process, and fork+exec and process. They |
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67 | have different advantages and disadvantages that I describe below, |
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68 | together with how this module tries to mitigate the disadvantages. |
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69 | |
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70 | =over 4 |
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71 | |
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72 | =item Forking from a big process can be very slow. |
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73 | |
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74 | A 5GB process needs 0.05s to fork on my 3.6GHz amd64 GNU/Linux box. This |
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75 | overhead is often shared with exec (because you have to fork first), but |
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76 | in some circumstances (e.g. when vfork is used), fork+exec can be much |
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77 | faster. |
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78 | |
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79 | This module can help here by telling a small(er) helper process to fork, |
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80 | which is faster then forking the main process, and also uses vfork where |
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81 | possible. This gives the speed of vfork, with the flexibility of fork. |
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82 | |
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83 | =item Forking usually creates a copy-on-write copy of the parent |
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84 | process. |
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85 | |
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86 | For example, modules or data files that are loaded will not use additional |
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87 | memory after a fork. When exec'ing a new process, modules and data files |
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88 | might need to be loaded again, at extra CPU and memory cost. But when |
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89 | forking, literally all data structures are copied - if the program frees |
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90 | them and replaces them by new data, the child processes will retain the |
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91 | old version even if it isn't used, which can suddenly and unexpectedly |
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92 | increase memory usage when freeing memory. |
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93 | |
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94 | The trade-off is between more sharing with fork (which can be good or |
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95 | bad), and no sharing with exec. |
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96 | |
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97 | This module allows the main program to do a controlled fork, and allows |
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98 | modules to exec processes safely at any time. When creating a custom |
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99 | process pool you can take advantage of data sharing via fork without |
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100 | risking to share large dynamic data structures that will blow up child |
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101 | memory usage. |
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102 | |
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103 | In other words, this module puts you into control over what is being |
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104 | shared and what isn't, at all times. |
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105 | |
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106 | =item Exec'ing a new perl process might be difficult. |
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107 | |
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108 | For example, it is not easy to find the correct path to the perl |
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109 | interpreter - C<$^X> might not be a perl interpreter at all. |
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110 | |
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111 | This module tries hard to identify the correct path to the perl |
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112 | interpreter. With a cooperative main program, exec'ing the interpreter |
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113 | might not even be necessary, but even without help from the main program, |
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114 | it will still work when used from a module. |
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115 | |
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116 | =item Exec'ing a new perl process might be slow, as all necessary modules |
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117 | have to be loaded from disk again, with no guarantees of success. |
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118 | |
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119 | Long running processes might run into problems when perl is upgraded |
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120 | and modules are no longer loadable because they refer to a different |
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121 | perl version, or parts of a distribution are newer than the ones already |
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122 | loaded. |
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123 | |
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124 | This module supports creating pre-initialised perl processes to be used as |
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125 | a template for new processes. |
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126 | |
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127 | =item Forking might be impossible when a program is running. |
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128 | |
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129 | For example, POSIX makes it almost impossible to fork from a |
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130 | multi-threaded program while doing anything useful in the child - in |
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131 | fact, if your perl program uses POSIX threads (even indirectly via |
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132 | e.g. L<IO::AIO> or L<threads>), you cannot call fork on the perl level |
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133 | anymore without risking corruption issues on a number of operating |
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134 | systems. |
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135 | |
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136 | This module can safely fork helper processes at any time, by calling |
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137 | fork+exec in C, in a POSIX-compatible way (via L<Proc::FastSpawn>). |
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138 | |
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139 | =item Parallel processing with fork might be inconvenient or difficult |
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140 | to implement. Modules might not work in both parent and child. |
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141 | |
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142 | For example, when a program uses an event loop and creates watchers it |
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143 | becomes very hard to use the event loop from a child program, as the |
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144 | watchers already exist but are only meaningful in the parent. Worse, a |
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145 | module might want to use such a module, not knowing whether another module |
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146 | or the main program also does, leading to problems. |
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147 | |
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148 | Apart from event loops, graphical toolkits also commonly fall into the |
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149 | "unsafe module" category, or just about anything that communicates with |
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150 | the external world, such as network libraries and file I/O modules, which |
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151 | usually don't like being copied and then allowed to continue in two |
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152 | processes. |
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153 | |
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154 | With this module only the main program is allowed to create new processes |
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155 | by forking (because only the main program can know when it is still safe |
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156 | to do so) - all other processes are created via fork+exec, which makes it |
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157 | possible to use modules such as event loops or window interfaces safely. |
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158 | |
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159 | =back |
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160 | |
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161 | =head1 EXAMPLES |
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162 | |
13 | # create a single new process, tell it to run your worker function |
163 | =head2 Create a single new process, tell it to run your worker function. |
14 | |
164 | |
15 | AnyEvent::Fork |
165 | AnyEvent::Fork |
16 | ->new |
166 | ->new |
17 | ->require ("MyModule") |
167 | ->require ("MyModule") |
18 | ->run ("MyModule::worker, sub { |
168 | ->run ("MyModule::worker, sub { |
… | |
… | |
20 | |
170 | |
21 | # now $master_filehandle is connected to the |
171 | # now $master_filehandle is connected to the |
22 | # $slave_filehandle in the new process. |
172 | # $slave_filehandle in the new process. |
23 | }); |
173 | }); |
24 | |
174 | |
25 | # MyModule::worker might look like this |
175 | C<MyModule> might look like this: |
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176 | |
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177 | package MyModule; |
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178 | |
26 | sub MyModule::worker { |
179 | sub worker { |
27 | my ($slave_filehandle) = @_; |
180 | my ($slave_filehandle) = @_; |
28 | |
181 | |
29 | # now $slave_filehandle is connected to the $master_filehandle |
182 | # now $slave_filehandle is connected to the $master_filehandle |
30 | # in the original prorcess. have fun! |
183 | # in the original prorcess. have fun! |
31 | } |
184 | } |
32 | |
185 | |
33 | ################################################################## |
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34 | # create a pool of server processes all accepting on the same socket |
186 | =head2 Create a pool of server processes all accepting on the same socket. |
35 | |
187 | |
36 | # create listener socket |
188 | # create listener socket |
37 | my $listener = ...; |
189 | my $listener = ...; |
38 | |
190 | |
39 | # create a pool template, initialise it and give it the socket |
191 | # create a pool template, initialise it and give it the socket |
… | |
… | |
51 | } |
203 | } |
52 | |
204 | |
53 | # now do other things - maybe use the filehandle provided by run |
205 | # now do other things - maybe use the filehandle provided by run |
54 | # to wait for the processes to die. or whatever. |
206 | # to wait for the processes to die. or whatever. |
55 | |
207 | |
56 | # My::Server::run might look like this |
208 | C<My::Server> might look like this: |
57 | sub My::Server::run { |
209 | |
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210 | package My::Server; |
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211 | |
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212 | sub run { |
58 | my ($slave, $listener, $id) = @_; |
213 | my ($slave, $listener, $id) = @_; |
59 | |
214 | |
60 | close $slave; # we do not use the socket, so close it to save resources |
215 | close $slave; # we do not use the socket, so close it to save resources |
61 | |
216 | |
62 | # we could go ballistic and use e.g. AnyEvent here, or IO::AIO, |
217 | # we could go ballistic and use e.g. AnyEvent here, or IO::AIO, |
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64 | while (my $socket = $listener->accept) { |
219 | while (my $socket = $listener->accept) { |
65 | # do sth. with new socket |
220 | # do sth. with new socket |
66 | } |
221 | } |
67 | } |
222 | } |
68 | |
223 | |
69 | =head1 DESCRIPTION |
224 | =head2 use AnyEvent::Fork as a faster fork+exec |
70 | |
225 | |
71 | This module allows you to create new processes, without actually forking |
226 | This runs C</bin/echo hi>, with stdandard output redirected to /tmp/log |
72 | them from your current process (avoiding the problems of forking), but |
227 | and standard error redirected to the communications socket. It is usually |
73 | preserving most of the advantages of fork. |
228 | faster than fork+exec, but still lets you prepare the environment. |
74 | |
229 | |
75 | It can be used to create new worker processes or new independent |
230 | open my $output, ">/tmp/log" or die "$!"; |
76 | subprocesses for short- and long-running jobs, process pools (e.g. for use |
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77 | in pre-forked servers) but also to spawn new external processes (such as |
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78 | CGI scripts from a webserver), which can be faster (and more well behaved) |
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79 | than using fork+exec in big processes. |
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80 | |
231 | |
81 | Special care has been taken to make this module useful from other modules, |
232 | AnyEvent::Fork |
82 | while still supporting specialised environments such as L<App::Staticperl> |
233 | ->new |
83 | or L<PAR::Packer>. |
234 | ->eval (' |
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235 | sub run { |
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236 | my ($fh, $output, @cmd) = @_; |
84 | |
237 | |
85 | =head1 PROBLEM STATEMENT |
238 | # perl will clear close-on-exec on STDOUT/STDERR |
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239 | open STDOUT, ">&", $output or die; |
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240 | open STDERR, ">&", $fh or die; |
86 | |
241 | |
87 | There are two ways to implement parallel processing on UNIX like operating |
242 | exec @cmd; |
88 | systems - fork and process, and fork+exec and process. They have different |
243 | } |
89 | advantages and disadvantages that I describe below, together with how this |
244 | ') |
90 | module tries to mitigate the disadvantages. |
245 | ->send_fh ($output) |
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246 | ->send_arg ("/bin/echo", "hi") |
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247 | ->run ("run", my $cv = AE::cv); |
91 | |
248 | |
92 | =over 4 |
249 | my $stderr = $cv->recv; |
93 | |
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94 | =item Forking from a big process can be very slow (a 5GB process needs |
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95 | 0.05s to fork on my 3.6GHz amd64 GNU/Linux box for example). This overhead |
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96 | is often shared with exec (because you have to fork first), but in some |
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97 | circumstances (e.g. when vfork is used), fork+exec can be much faster. |
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98 | |
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99 | This module can help here by telling a small(er) helper process to fork, |
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100 | or fork+exec instead. |
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101 | |
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102 | =item Forking usually creates a copy-on-write copy of the parent |
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103 | process. Memory (for example, modules or data files that have been |
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104 | will not take additional memory). When exec'ing a new process, modules |
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105 | and data files might need to be loaded again, at extra cpu and memory |
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106 | cost. Likewise when forking, all data structures are copied as well - if |
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107 | the program frees them and replaces them by new data, the child processes |
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108 | will retain the memory even if it isn't used. |
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109 | |
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110 | This module allows the main program to do a controlled fork, and allows |
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111 | modules to exec processes safely at any time. When creating a custom |
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112 | process pool you can take advantage of data sharing via fork without |
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113 | risking to share large dynamic data structures that will blow up child |
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114 | memory usage. |
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115 | |
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116 | =item Exec'ing a new perl process might be difficult and slow. For |
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117 | example, it is not easy to find the correct path to the perl interpreter, |
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118 | and all modules have to be loaded from disk again. Long running processes |
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119 | might run into problems when perl is upgraded for example. |
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120 | |
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121 | This module supports creating pre-initialised perl processes to be used |
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122 | as template, and also tries hard to identify the correct path to the perl |
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123 | interpreter. With a cooperative main program, exec'ing the interpreter |
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124 | might not even be necessary. |
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125 | |
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126 | =item Forking might be impossible when a program is running. For example, |
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127 | POSIX makes it almost impossible to fork from a multithreaded program and |
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128 | do anything useful in the child - strictly speaking, if your perl program |
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129 | uses posix threads (even indirectly via e.g. L<IO::AIO> or L<threads>), |
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130 | you cannot call fork on the perl level anymore, at all. |
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131 | |
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132 | This module can safely fork helper processes at any time, by caling |
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133 | fork+exec in C, in a POSIX-compatible way. |
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134 | |
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135 | =item Parallel processing with fork might be inconvenient or difficult |
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136 | to implement. For example, when a program uses an event loop and creates |
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137 | watchers it becomes very hard to use the event loop from a child |
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138 | program, as the watchers already exist but are only meaningful in the |
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139 | parent. Worse, a module might want to use such a system, not knowing |
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140 | whether another module or the main program also does, leading to problems. |
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141 | |
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142 | This module only lets the main program create pools by forking (because |
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143 | only the main program can know when it is still safe to do so) - all other |
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144 | pools are created by fork+exec, after which such modules can again be |
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145 | loaded. |
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146 | |
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147 | =back |
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148 | |
250 | |
149 | =head1 CONCEPTS |
251 | =head1 CONCEPTS |
150 | |
252 | |
151 | This module can create new processes either by executing a new perl |
253 | This module can create new processes either by executing a new perl |
152 | process, or by forking from an existing "template" process. |
254 | process, or by forking from an existing "template" process. |
… | |
… | |
169 | needed the first time. Forking from this process shares the memory used |
271 | needed the first time. Forking from this process shares the memory used |
170 | for the perl interpreter with the new process, but loading modules takes |
272 | for the perl interpreter with the new process, but loading modules takes |
171 | time, and the memory is not shared with anything else. |
273 | time, and the memory is not shared with anything else. |
172 | |
274 | |
173 | This is ideal for when you only need one extra process of a kind, with the |
275 | This is ideal for when you only need one extra process of a kind, with the |
174 | option of starting and stipping it on demand. |
276 | option of starting and stopping it on demand. |
175 | |
277 | |
176 | Example: |
278 | Example: |
177 | |
279 | |
178 | AnyEvent::Fork |
280 | AnyEvent::Fork |
179 | ->new |
281 | ->new |
… | |
… | |
194 | modules you loaded) is shared between the processes, and each new process |
296 | modules you loaded) is shared between the processes, and each new process |
195 | consumes relatively little memory of its own. |
297 | consumes relatively little memory of its own. |
196 | |
298 | |
197 | The disadvantage of this approach is that you need to create a template |
299 | The disadvantage of this approach is that you need to create a template |
198 | process for the sole purpose of forking new processes from it, but if you |
300 | process for the sole purpose of forking new processes from it, but if you |
199 | only need a fixed number of proceses you can create them, and then destroy |
301 | only need a fixed number of processes you can create them, and then destroy |
200 | the template process. |
302 | the template process. |
201 | |
303 | |
202 | Example: |
304 | Example: |
203 | |
305 | |
204 | my $template = AnyEvent::Fork->new->require ("Some::Module"); |
306 | my $template = AnyEvent::Fork->new->require ("Some::Module"); |
… | |
… | |
231 | my ($fork_fh) = @_; |
333 | my ($fork_fh) = @_; |
232 | }); |
334 | }); |
233 | |
335 | |
234 | =back |
336 | =back |
235 | |
337 | |
236 | =head1 FUNCTIONS |
338 | =head1 THE C<AnyEvent::Fork> CLASS |
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339 | |
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340 | This module exports nothing, and only implements a single class - |
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341 | C<AnyEvent::Fork>. |
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342 | |
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343 | There are two class constructors that both create new processes - C<new> |
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344 | and C<new_exec>. The C<fork> method creates a new process by forking an |
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345 | existing one and could be considered a third constructor. |
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346 | |
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347 | Most of the remaining methods deal with preparing the new process, by |
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348 | loading code, evaluating code and sending data to the new process. They |
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349 | usually return the process object, so you can chain method calls. |
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350 | |
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351 | If a process object is destroyed before calling its C<run> method, then |
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352 | the process simply exits. After C<run> is called, all responsibility is |
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353 | passed to the specified function. |
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354 | |
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355 | As long as there is any outstanding work to be done, process objects |
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356 | resist being destroyed, so there is no reason to store them unless you |
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357 | need them later - configure and forget works just fine. |
237 | |
358 | |
238 | =over 4 |
359 | =over 4 |
239 | |
360 | |
240 | =cut |
361 | =cut |
241 | |
362 | |
242 | package AnyEvent::Fork; |
363 | package AnyEvent::Fork; |
243 | |
364 | |
244 | use common::sense; |
365 | use common::sense; |
245 | |
366 | |
246 | use Socket (); |
367 | use Errno (); |
247 | |
368 | |
248 | use AnyEvent; |
369 | use AnyEvent; |
249 | use AnyEvent::Fork::Util; |
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250 | use AnyEvent::Util (); |
370 | use AnyEvent::Util (); |
251 | |
371 | |
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372 | use IO::FDPass; |
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373 | |
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374 | our $VERSION = 0.5; |
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375 | |
252 | our $PERL; # the path to the perl interpreter, deduces with various forms of magic |
376 | our $PERL; # the path to the perl interpreter, deduces with various forms of magic |
253 | |
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254 | =item my $pool = new AnyEvent::Fork key => value... |
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255 | |
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256 | Create a new process pool. The following named parameters are supported: |
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257 | |
377 | |
258 | =over 4 |
378 | =over 4 |
259 | |
379 | |
260 | =back |
380 | =back |
261 | |
381 | |
… | |
… | |
268 | our $TEMPLATE; |
388 | our $TEMPLATE; |
269 | |
389 | |
270 | sub _cmd { |
390 | sub _cmd { |
271 | my $self = shift; |
391 | my $self = shift; |
272 | |
392 | |
273 | #TODO: maybe append the packet to any existing string command already in the queue |
|
|
274 | |
|
|
275 | # ideally, we would want to use "a (w/a)*" as format string, but perl versions |
393 | # ideally, we would want to use "a (w/a)*" as format string, but perl |
276 | # from at least 5.8.9 to 5.16.3 are all buggy and can't unpack it. |
394 | # versions from at least 5.8.9 to 5.16.3 are all buggy and can't unpack |
277 | push @{ $self->[2] }, pack "N/a*", pack "(w/a*)*", @_; |
395 | # it. |
|
|
396 | push @{ $self->[2] }, pack "a L/a*", $_[0], $_[1]; |
278 | |
397 | |
279 | $self->[3] ||= AE::io $self->[1], 1, sub { |
398 | $self->[3] ||= AE::io $self->[1], 1, sub { |
|
|
399 | do { |
280 | # send the next "thing" in the queue - either a reference to an fh, |
400 | # send the next "thing" in the queue - either a reference to an fh, |
281 | # or a plain string. |
401 | # or a plain string. |
282 | |
402 | |
283 | if (ref $self->[2][0]) { |
403 | if (ref $self->[2][0]) { |
284 | # send fh |
404 | # send fh |
285 | AnyEvent::Fork::Util::fd_send fileno $self->[1], fileno ${ $self->[2][0] } |
405 | unless (IO::FDPass::send fileno $self->[1], fileno ${ $self->[2][0] }) { |
|
|
406 | return if $! == Errno::EAGAIN || $! == Errno::EWOULDBLOCK; |
|
|
407 | undef $self->[3]; |
|
|
408 | die "AnyEvent::Fork: file descriptor send failure: $!"; |
|
|
409 | } |
|
|
410 | |
286 | and shift @{ $self->[2] }; |
411 | shift @{ $self->[2] }; |
287 | |
412 | |
288 | } else { |
413 | } else { |
289 | # send string |
414 | # send string |
290 | my $len = syswrite $self->[1], $self->[2][0] |
415 | my $len = syswrite $self->[1], $self->[2][0]; |
|
|
416 | |
|
|
417 | unless ($len) { |
|
|
418 | return if $! == Errno::EAGAIN || $! == Errno::EWOULDBLOCK; |
|
|
419 | undef $self->[3]; |
291 | or do { undef $self->[3]; die "AnyEvent::Fork: command write failure: $!" }; |
420 | die "AnyEvent::Fork: command write failure: $!"; |
|
|
421 | } |
292 | |
422 | |
293 | substr $self->[2][0], 0, $len, ""; |
423 | substr $self->[2][0], 0, $len, ""; |
294 | shift @{ $self->[2] } unless length $self->[2][0]; |
424 | shift @{ $self->[2] } unless length $self->[2][0]; |
295 | } |
425 | } |
|
|
426 | } while @{ $self->[2] }; |
296 | |
427 | |
297 | unless (@{ $self->[2] }) { |
428 | # everything written |
298 | undef $self->[3]; |
429 | undef $self->[3]; |
|
|
430 | |
299 | # invoke run callback |
431 | # invoke run callback, if any |
300 | $self->[0]->($self->[1]) if $self->[0]; |
432 | $self->[4]->($self->[1]) if $self->[4]; |
301 | } |
|
|
302 | }; |
433 | }; |
|
|
434 | |
|
|
435 | () # make sure we don't leak the watcher |
303 | } |
436 | } |
304 | |
437 | |
305 | sub _new { |
438 | sub _new { |
306 | my ($self, $fh) = @_; |
439 | my ($self, $fh, $pid) = @_; |
307 | |
440 | |
308 | AnyEvent::Util::fh_nonblocking $fh, 1; |
441 | AnyEvent::Util::fh_nonblocking $fh, 1; |
309 | |
442 | |
310 | $self = bless [ |
443 | $self = bless [ |
311 | undef, # run callback |
444 | $pid, |
312 | $fh, |
445 | $fh, |
313 | [], # write queue - strings or fd's |
446 | [], # write queue - strings or fd's |
314 | undef, # AE watcher |
447 | undef, # AE watcher |
315 | ], $self; |
448 | ], $self; |
316 | |
449 | |
… | |
… | |
327 | if ($pid eq 0) { |
460 | if ($pid eq 0) { |
328 | require AnyEvent::Fork::Serve; |
461 | require AnyEvent::Fork::Serve; |
329 | $AnyEvent::Fork::Serve::OWNER = $parent; |
462 | $AnyEvent::Fork::Serve::OWNER = $parent; |
330 | close $fh; |
463 | close $fh; |
331 | $0 = "$_[1] of $parent"; |
464 | $0 = "$_[1] of $parent"; |
|
|
465 | $SIG{CHLD} = 'IGNORE'; |
332 | AnyEvent::Fork::Serve::serve ($slave); |
466 | AnyEvent::Fork::Serve::serve ($slave); |
333 | AnyEvent::Fork::Util::_exit 0; |
467 | exit 0; |
334 | } elsif (!$pid) { |
468 | } elsif (!$pid) { |
335 | die "AnyEvent::Fork::Early/Template: unable to fork template process: $!"; |
469 | die "AnyEvent::Fork::Early/Template: unable to fork template process: $!"; |
336 | } |
470 | } |
337 | |
471 | |
338 | AnyEvent::Fork->_new ($fh) |
472 | AnyEvent::Fork->_new ($fh, $pid) |
339 | } |
473 | } |
340 | |
474 | |
341 | =item my $proc = new AnyEvent::Fork |
475 | =item my $proc = new AnyEvent::Fork |
342 | |
476 | |
343 | Create a new "empty" perl interpreter process and returns its process |
477 | Create a new "empty" perl interpreter process and returns its process |
344 | object for further manipulation. |
478 | object for further manipulation. |
345 | |
479 | |
346 | The new process is forked from a template process that is kept around |
480 | The new process is forked from a template process that is kept around |
347 | for this purpose. When it doesn't exist yet, it is created by a call to |
481 | for this purpose. When it doesn't exist yet, it is created by a call to |
348 | C<new_exec> and kept around for future calls. |
482 | C<new_exec> first and then stays around for future calls. |
349 | |
|
|
350 | When the process object is destroyed, it will release the file handle |
|
|
351 | that connects it with the new process. When the new process has not yet |
|
|
352 | called C<run>, then the process will exit. Otherwise, what happens depends |
|
|
353 | entirely on the code that is executed. |
|
|
354 | |
483 | |
355 | =cut |
484 | =cut |
356 | |
485 | |
357 | sub new { |
486 | sub new { |
358 | my $class = shift; |
487 | my $class = shift; |
… | |
… | |
394 | reduces the amount of memory sharing that is possible, and is also slower. |
523 | reduces the amount of memory sharing that is possible, and is also slower. |
395 | |
524 | |
396 | You should use C<new> whenever possible, except when having a template |
525 | You should use C<new> whenever possible, except when having a template |
397 | process around is unacceptable. |
526 | process around is unacceptable. |
398 | |
527 | |
399 | The path to the perl interpreter is divined usign various methods - first |
528 | The path to the perl interpreter is divined using various methods - first |
400 | C<$^X> is investigated to see if the path ends with something that sounds |
529 | C<$^X> is investigated to see if the path ends with something that sounds |
401 | as if it were the perl interpreter. Failing this, the module falls back to |
530 | as if it were the perl interpreter. Failing this, the module falls back to |
402 | using C<$Config::Config{perlpath}>. |
531 | using C<$Config::Config{perlpath}>. |
403 | |
532 | |
404 | =cut |
533 | =cut |
… | |
… | |
413 | my $perl = $; |
542 | my $perl = $; |
414 | |
543 | |
415 | # first we try $^X, but the path must be absolute (always on win32), and end in sth. |
544 | # first we try $^X, but the path must be absolute (always on win32), and end in sth. |
416 | # that looks like perl. this obviously only works for posix and win32 |
545 | # that looks like perl. this obviously only works for posix and win32 |
417 | unless ( |
546 | unless ( |
418 | (AnyEvent::Fork::Util::WIN32 || $perl =~ m%^/%) |
547 | ($^O eq "MSWin32" || $perl =~ m%^/%) |
419 | && $perl =~ m%[/\\]perl(?:[0-9]+(\.[0-9]+)+)?(\.exe)?$%i |
548 | && $perl =~ m%[/\\]perl(?:[0-9]+(\.[0-9]+)+)?(\.exe)?$%i |
420 | ) { |
549 | ) { |
421 | # if it doesn't look perlish enough, try Config |
550 | # if it doesn't look perlish enough, try Config |
422 | require Config; |
551 | require Config; |
423 | $perl = $Config::Config{perlpath}; |
552 | $perl = $Config::Config{perlpath}; |
… | |
… | |
434 | Proc::FastSpawn::fd_inherit (fileno $fh, 0); |
563 | Proc::FastSpawn::fd_inherit (fileno $fh, 0); |
435 | |
564 | |
436 | # quick. also doesn't work in win32. of course. what did you expect |
565 | # quick. also doesn't work in win32. of course. what did you expect |
437 | #local $ENV{PERL5LIB} = join ":", grep !ref, @INC; |
566 | #local $ENV{PERL5LIB} = join ":", grep !ref, @INC; |
438 | my %env = %ENV; |
567 | my %env = %ENV; |
439 | $env{PERL5LIB} = join +(AnyEvent::Fork::Util::WIN32 ? ";" : ":"), grep !ref, @INC; |
568 | $env{PERL5LIB} = join +($^O eq "MSWin32" ? ";" : ":"), grep !ref, @INC; |
440 | |
569 | |
441 | Proc::FastSpawn::spawn ( |
570 | my $pid = Proc::FastSpawn::spawn ( |
442 | $perl, |
571 | $perl, |
443 | ["perl", "-MAnyEvent::Fork::Serve", "-e", "AnyEvent::Fork::Serve::me", fileno $slave, $$], |
572 | ["perl", "-MAnyEvent::Fork::Serve", "-e", "AnyEvent::Fork::Serve::me", fileno $slave, $$], |
444 | [map "$_=$env{$_}", keys %env], |
573 | [map "$_=$env{$_}", keys %env], |
445 | ) or die "unable to spawn AnyEvent::Fork server: $!"; |
574 | ) or die "unable to spawn AnyEvent::Fork server: $!"; |
446 | |
575 | |
447 | $self->_new ($fh) |
576 | $self->_new ($fh, $pid) |
|
|
577 | } |
|
|
578 | |
|
|
579 | =item $pid = $proc->pid |
|
|
580 | |
|
|
581 | Returns the process id of the process I<iff it is a direct child of the |
|
|
582 | process running AnyEvent::Fork>, and C<undef> otherwise. |
|
|
583 | |
|
|
584 | Normally, only processes created via C<< AnyEvent::Fork->new_exec >> and |
|
|
585 | L<AnyEvent::Fork::Template> are direct children, and you are responsible |
|
|
586 | to clean up their zombies when they die. |
|
|
587 | |
|
|
588 | All other processes are not direct children, and will be cleaned up by |
|
|
589 | AnyEvent::Fork itself. |
|
|
590 | |
|
|
591 | =cut |
|
|
592 | |
|
|
593 | sub pid { |
|
|
594 | $_[0][0] |
448 | } |
595 | } |
449 | |
596 | |
450 | =item $proc = $proc->eval ($perlcode, @args) |
597 | =item $proc = $proc->eval ($perlcode, @args) |
451 | |
598 | |
452 | Evaluates the given C<$perlcode> as ... perl code, while setting C<@_> to |
599 | Evaluates the given C<$perlcode> as ... perl code, while setting C<@_> to |
453 | the strings specified by C<@args>. |
600 | the strings specified by C<@args>, in the "main" package. |
454 | |
601 | |
455 | This call is meant to do any custom initialisation that might be required |
602 | This call is meant to do any custom initialisation that might be required |
456 | (for example, the C<require> method uses it). It's not supposed to be used |
603 | (for example, the C<require> method uses it). It's not supposed to be used |
457 | to completely take over the process, use C<run> for that. |
604 | to completely take over the process, use C<run> for that. |
458 | |
605 | |
459 | The code will usually be executed after this call returns, and there is no |
606 | The code will usually be executed after this call returns, and there is no |
460 | way to pass anything back to the calling process. Any evaluation errors |
607 | way to pass anything back to the calling process. Any evaluation errors |
461 | will be reported to stderr and cause the process to exit. |
608 | will be reported to stderr and cause the process to exit. |
462 | |
609 | |
|
|
610 | If you want to execute some code (that isn't in a module) to take over the |
|
|
611 | process, you should compile a function via C<eval> first, and then call |
|
|
612 | it via C<run>. This also gives you access to any arguments passed via the |
|
|
613 | C<send_xxx> methods, such as file handles. See the L<use AnyEvent::Fork as |
|
|
614 | a faster fork+exec> example to see it in action. |
|
|
615 | |
463 | Returns the process object for easy chaining of method calls. |
616 | Returns the process object for easy chaining of method calls. |
464 | |
617 | |
465 | =cut |
618 | =cut |
466 | |
619 | |
467 | sub eval { |
620 | sub eval { |
468 | my ($self, $code, @args) = @_; |
621 | my ($self, $code, @args) = @_; |
469 | |
622 | |
470 | $self->_cmd (e => $code, @args); |
623 | $self->_cmd (e => pack "(w/a*)*", $code, @args); |
471 | |
624 | |
472 | $self |
625 | $self |
473 | } |
626 | } |
474 | |
627 | |
475 | =item $proc = $proc->require ($module, ...) |
628 | =item $proc = $proc->require ($module, ...) |
… | |
… | |
492 | =item $proc = $proc->send_fh ($handle, ...) |
645 | =item $proc = $proc->send_fh ($handle, ...) |
493 | |
646 | |
494 | Send one or more file handles (I<not> file descriptors) to the process, |
647 | Send one or more file handles (I<not> file descriptors) to the process, |
495 | to prepare a call to C<run>. |
648 | to prepare a call to C<run>. |
496 | |
649 | |
497 | The process object keeps a reference to the handles until this is done, |
650 | The process object keeps a reference to the handles until they have |
498 | so you must not explicitly close the handles. This is most easily |
651 | been passed over to the process, so you must not explicitly close the |
499 | accomplished by simply not storing the file handles anywhere after passing |
652 | handles. This is most easily accomplished by simply not storing the file |
500 | them to this method. |
653 | handles anywhere after passing them to this method - when AnyEvent::Fork |
|
|
654 | is finished using them, perl will automatically close them. |
501 | |
655 | |
502 | Returns the process object for easy chaining of method calls. |
656 | Returns the process object for easy chaining of method calls. |
503 | |
657 | |
504 | Example: pass an fh to a process, and release it without closing. it will |
658 | Example: pass a file handle to a process, and release it without |
505 | be closed automatically when it is no longer used. |
659 | closing. It will be closed automatically when it is no longer used. |
506 | |
660 | |
507 | $proc->send_fh ($my_fh); |
661 | $proc->send_fh ($my_fh); |
508 | undef $my_fh; # free the reference if you want, but DO NOT CLOSE IT |
662 | undef $my_fh; # free the reference if you want, but DO NOT CLOSE IT |
509 | |
663 | |
510 | =cut |
664 | =cut |
… | |
… | |
521 | } |
675 | } |
522 | |
676 | |
523 | =item $proc = $proc->send_arg ($string, ...) |
677 | =item $proc = $proc->send_arg ($string, ...) |
524 | |
678 | |
525 | Send one or more argument strings to the process, to prepare a call to |
679 | Send one or more argument strings to the process, to prepare a call to |
526 | C<run>. The strings can be any octet string. |
680 | C<run>. The strings can be any octet strings. |
527 | |
681 | |
|
|
682 | The protocol is optimised to pass a moderate number of relatively short |
|
|
683 | strings - while you can pass up to 4GB of data in one go, this is more |
|
|
684 | meant to pass some ID information or other startup info, not big chunks of |
|
|
685 | data. |
|
|
686 | |
528 | Returns the process object for easy chaining of emthod calls. |
687 | Returns the process object for easy chaining of method calls. |
529 | |
688 | |
530 | =cut |
689 | =cut |
531 | |
690 | |
532 | sub send_arg { |
691 | sub send_arg { |
533 | my ($self, @arg) = @_; |
692 | my ($self, @arg) = @_; |
534 | |
693 | |
535 | $self->_cmd (a => @arg); |
694 | $self->_cmd (a => pack "(w/a*)*", @arg); |
536 | |
695 | |
537 | $self |
696 | $self |
538 | } |
697 | } |
539 | |
698 | |
540 | =item $proc->run ($func, $cb->($fh)) |
699 | =item $proc->run ($func, $cb->($fh)) |
541 | |
700 | |
542 | Enter the function specified by the fully qualified name in C<$func> in |
701 | Enter the function specified by the function name in C<$func> in the |
543 | the process. The function is called with the communication socket as first |
702 | process. The function is called with the communication socket as first |
544 | argument, followed by all file handles and string arguments sent earlier |
703 | argument, followed by all file handles and string arguments sent earlier |
545 | via C<send_fh> and C<send_arg> methods, in the order they were called. |
704 | via C<send_fh> and C<send_arg> methods, in the order they were called. |
546 | |
705 | |
547 | If the called function returns, the process exits. |
|
|
548 | |
|
|
549 | Preparing the process can take time - when the process is ready, the |
|
|
550 | callback is invoked with the local communications socket as argument. |
|
|
551 | |
|
|
552 | The process object becomes unusable on return from this function. |
706 | The process object becomes unusable on return from this function - any |
|
|
707 | further method calls result in undefined behaviour. |
|
|
708 | |
|
|
709 | The function name should be fully qualified, but if it isn't, it will be |
|
|
710 | looked up in the C<main> package. |
|
|
711 | |
|
|
712 | If the called function returns, doesn't exist, or any error occurs, the |
|
|
713 | process exits. |
|
|
714 | |
|
|
715 | Preparing the process is done in the background - when all commands have |
|
|
716 | been sent, the callback is invoked with the local communications socket |
|
|
717 | as argument. At this point you can start using the socket in any way you |
|
|
718 | like. |
553 | |
719 | |
554 | If the communication socket isn't used, it should be closed on both sides, |
720 | If the communication socket isn't used, it should be closed on both sides, |
555 | to save on kernel memory. |
721 | to save on kernel memory. |
556 | |
722 | |
557 | The socket is non-blocking in the parent, and blocking in the newly |
723 | The socket is non-blocking in the parent, and blocking in the newly |
558 | created process. The close-on-exec flag is set on both. Even if not used |
724 | created process. The close-on-exec flag is set in both. |
|
|
725 | |
559 | otherwise, the socket can be a good indicator for the existance of the |
726 | Even if not used otherwise, the socket can be a good indicator for the |
560 | process - if the other process exits, you get a readable event on it, |
727 | existence of the process - if the other process exits, you get a readable |
561 | because exiting the process closes the socket (if it didn't create any |
728 | event on it, because exiting the process closes the socket (if it didn't |
562 | children using fork). |
729 | create any children using fork). |
563 | |
730 | |
564 | Example: create a template for a process pool, pass a few strings, some |
731 | Example: create a template for a process pool, pass a few strings, some |
565 | file handles, then fork, pass one more string, and run some code. |
732 | file handles, then fork, pass one more string, and run some code. |
566 | |
733 | |
567 | my $pool = AnyEvent::Fork |
734 | my $pool = AnyEvent::Fork |
… | |
… | |
575 | ->send_arg ("str3") |
742 | ->send_arg ("str3") |
576 | ->run ("Some::function", sub { |
743 | ->run ("Some::function", sub { |
577 | my ($fh) = @_; |
744 | my ($fh) = @_; |
578 | |
745 | |
579 | # fh is nonblocking, but we trust that the OS can accept these |
746 | # fh is nonblocking, but we trust that the OS can accept these |
580 | # extra 3 octets anyway. |
747 | # few octets anyway. |
581 | syswrite $fh, "hi #$_\n"; |
748 | syswrite $fh, "hi #$_\n"; |
582 | |
749 | |
583 | # $fh is being closed here, as we don't store it anywhere |
750 | # $fh is being closed here, as we don't store it anywhere |
584 | }); |
751 | }); |
585 | } |
752 | } |
… | |
… | |
587 | # Some::function might look like this - all parameters passed before fork |
754 | # Some::function might look like this - all parameters passed before fork |
588 | # and after will be passed, in order, after the communications socket. |
755 | # and after will be passed, in order, after the communications socket. |
589 | sub Some::function { |
756 | sub Some::function { |
590 | my ($fh, $str1, $str2, $fh1, $fh2, $str3) = @_; |
757 | my ($fh, $str1, $str2, $fh1, $fh2, $str3) = @_; |
591 | |
758 | |
592 | print scalar <$fh>; # prints "hi 1\n" and "hi 2\n" |
759 | print scalar <$fh>; # prints "hi #1\n" and "hi #2\n" in any order |
593 | } |
760 | } |
594 | |
761 | |
595 | =cut |
762 | =cut |
596 | |
763 | |
597 | sub run { |
764 | sub run { |
598 | my ($self, $func, $cb) = @_; |
765 | my ($self, $func, $cb) = @_; |
599 | |
766 | |
600 | $self->[0] = $cb; |
767 | $self->[4] = $cb; |
601 | $self->_cmd (r => $func); |
768 | $self->_cmd (r => $func); |
602 | } |
769 | } |
|
|
770 | |
|
|
771 | =back |
|
|
772 | |
|
|
773 | =head1 PERFORMANCE |
|
|
774 | |
|
|
775 | Now for some unscientific benchmark numbers (all done on an amd64 |
|
|
776 | GNU/Linux box). These are intended to give you an idea of the relative |
|
|
777 | performance you can expect, they are not meant to be absolute performance |
|
|
778 | numbers. |
|
|
779 | |
|
|
780 | OK, so, I ran a simple benchmark that creates a socket pair, forks, calls |
|
|
781 | exit in the child and waits for the socket to close in the parent. I did |
|
|
782 | load AnyEvent, EV and AnyEvent::Fork, for a total process size of 5100kB. |
|
|
783 | |
|
|
784 | 2079 new processes per second, using manual socketpair + fork |
|
|
785 | |
|
|
786 | Then I did the same thing, but instead of calling fork, I called |
|
|
787 | AnyEvent::Fork->new->run ("CORE::exit") and then again waited for the |
|
|
788 | socket form the child to close on exit. This does the same thing as manual |
|
|
789 | socket pair + fork, except that what is forked is the template process |
|
|
790 | (2440kB), and the socket needs to be passed to the server at the other end |
|
|
791 | of the socket first. |
|
|
792 | |
|
|
793 | 2307 new processes per second, using AnyEvent::Fork->new |
|
|
794 | |
|
|
795 | And finally, using C<new_exec> instead C<new>, using vforks+execs to exec |
|
|
796 | a new perl interpreter and compile the small server each time, I get: |
|
|
797 | |
|
|
798 | 479 vfork+execs per second, using AnyEvent::Fork->new_exec |
|
|
799 | |
|
|
800 | So how can C<< AnyEvent->new >> be faster than a standard fork, even |
|
|
801 | though it uses the same operations, but adds a lot of overhead? |
|
|
802 | |
|
|
803 | The difference is simply the process size: forking the 5MB process takes |
|
|
804 | so much longer than forking the 2.5MB template process that the extra |
|
|
805 | overhead introduced is canceled out. |
|
|
806 | |
|
|
807 | If the benchmark process grows, the normal fork becomes even slower: |
|
|
808 | |
|
|
809 | 1340 new processes, manual fork of a 20MB process |
|
|
810 | 731 new processes, manual fork of a 200MB process |
|
|
811 | 235 new processes, manual fork of a 2000MB process |
|
|
812 | |
|
|
813 | What that means (to me) is that I can use this module without having a bad |
|
|
814 | conscience because of the extra overhead required to start new processes. |
|
|
815 | |
|
|
816 | =head1 TYPICAL PROBLEMS |
|
|
817 | |
|
|
818 | This section lists typical problems that remain. I hope by recognising |
|
|
819 | them, most can be avoided. |
|
|
820 | |
|
|
821 | =over 4 |
|
|
822 | |
|
|
823 | =item leaked file descriptors for exec'ed processes |
|
|
824 | |
|
|
825 | POSIX systems inherit file descriptors by default when exec'ing a new |
|
|
826 | process. While perl itself laudably sets the close-on-exec flags on new |
|
|
827 | file handles, most C libraries don't care, and even if all cared, it's |
|
|
828 | often not possible to set the flag in a race-free manner. |
|
|
829 | |
|
|
830 | That means some file descriptors can leak through. And since it isn't |
|
|
831 | possible to know which file descriptors are "good" and "necessary" (or |
|
|
832 | even to know which file descriptors are open), there is no good way to |
|
|
833 | close the ones that might harm. |
|
|
834 | |
|
|
835 | As an example of what "harm" can be done consider a web server that |
|
|
836 | accepts connections and afterwards some module uses AnyEvent::Fork for the |
|
|
837 | first time, causing it to fork and exec a new process, which might inherit |
|
|
838 | the network socket. When the server closes the socket, it is still open |
|
|
839 | in the child (which doesn't even know that) and the client might conclude |
|
|
840 | that the connection is still fine. |
|
|
841 | |
|
|
842 | For the main program, there are multiple remedies available - |
|
|
843 | L<AnyEvent::Fork::Early> is one, creating a process early and not using |
|
|
844 | C<new_exec> is another, as in both cases, the first process can be exec'ed |
|
|
845 | well before many random file descriptors are open. |
|
|
846 | |
|
|
847 | In general, the solution for these kind of problems is to fix the |
|
|
848 | libraries or the code that leaks those file descriptors. |
|
|
849 | |
|
|
850 | Fortunately, most of these leaked descriptors do no harm, other than |
|
|
851 | sitting on some resources. |
|
|
852 | |
|
|
853 | =item leaked file descriptors for fork'ed processes |
|
|
854 | |
|
|
855 | Normally, L<AnyEvent::Fork> does start new processes by exec'ing them, |
|
|
856 | which closes file descriptors not marked for being inherited. |
|
|
857 | |
|
|
858 | However, L<AnyEvent::Fork::Early> and L<AnyEvent::Fork::Template> offer |
|
|
859 | a way to create these processes by forking, and this leaks more file |
|
|
860 | descriptors than exec'ing them, as there is no way to mark descriptors as |
|
|
861 | "close on fork". |
|
|
862 | |
|
|
863 | An example would be modules like L<EV>, L<IO::AIO> or L<Gtk2>. Both create |
|
|
864 | pipes for internal uses, and L<Gtk2> might open a connection to the X |
|
|
865 | server. L<EV> and L<IO::AIO> can deal with fork, but Gtk2 might have |
|
|
866 | trouble with a fork. |
|
|
867 | |
|
|
868 | The solution is to either not load these modules before use'ing |
|
|
869 | L<AnyEvent::Fork::Early> or L<AnyEvent::Fork::Template>, or to delay |
|
|
870 | initialising them, for example, by calling C<init Gtk2> manually. |
|
|
871 | |
|
|
872 | =item exiting calls object destructors |
|
|
873 | |
|
|
874 | This only applies to users of L<AnyEvent::Fork:Early> and |
|
|
875 | L<AnyEvent::Fork::Template>, or when initialiasing code creates objects |
|
|
876 | that reference external resources. |
|
|
877 | |
|
|
878 | When a process created by AnyEvent::Fork exits, it might do so by calling |
|
|
879 | exit, or simply letting perl reach the end of the program. At which point |
|
|
880 | Perl runs all destructors. |
|
|
881 | |
|
|
882 | Not all destructors are fork-safe - for example, an object that represents |
|
|
883 | the connection to an X display might tell the X server to free resources, |
|
|
884 | which is inconvenient when the "real" object in the parent still needs to |
|
|
885 | use them. |
|
|
886 | |
|
|
887 | This is obviously not a problem for L<AnyEvent::Fork::Early>, as you used |
|
|
888 | it as the very first thing, right? |
|
|
889 | |
|
|
890 | It is a problem for L<AnyEvent::Fork::Template> though - and the solution |
|
|
891 | is to not create objects with nontrivial destructors that might have an |
|
|
892 | effect outside of Perl. |
603 | |
893 | |
604 | =back |
894 | =back |
605 | |
895 | |
606 | =head1 PORTABILITY NOTES |
896 | =head1 PORTABILITY NOTES |
607 | |
897 | |
608 | Native win32 perls are somewhat supported (AnyEvent::Fork::Early is a nop, |
898 | Native win32 perls are somewhat supported (AnyEvent::Fork::Early is a nop, |
609 | and ::Template is not going to work), and it cost a lot of blood and sweat |
899 | and ::Template is not going to work), and it cost a lot of blood and sweat |
610 | to make it so, mostly due to the bloody broken perl that nobody seems to |
900 | to make it so, mostly due to the bloody broken perl that nobody seems to |
611 | care about. The fork emulation is a bad joke - I have yet to see something |
901 | care about. The fork emulation is a bad joke - I have yet to see something |
612 | useful that you cna do with it without running into memory corruption |
902 | useful that you can do with it without running into memory corruption |
613 | issues or other braindamage. Hrrrr. |
903 | issues or other braindamage. Hrrrr. |
614 | |
904 | |
615 | Cygwin perl is not supported at the moment, as it should implement fd |
905 | Cygwin perl is not supported at the moment due to some hilarious |
616 | passing, but doesn't, and rolling my own is hard, as cygwin doesn't |
906 | shortcomings of its API - see L<IO::FDPoll> for more details. |
617 | support enough functionality to do it. |
907 | |
|
|
908 | =head1 SEE ALSO |
|
|
909 | |
|
|
910 | L<AnyEvent::Fork::Early> (to avoid executing a perl interpreter), |
|
|
911 | L<AnyEvent::Fork::Template> (to create a process by forking the main |
|
|
912 | program at a convenient time). |
618 | |
913 | |
619 | =head1 AUTHOR |
914 | =head1 AUTHOR |
620 | |
915 | |
621 | Marc Lehmann <schmorp@schmorp.de> |
916 | Marc Lehmann <schmorp@schmorp.de> |
622 | http://home.schmorp.de/ |
917 | http://home.schmorp.de/ |