… | |
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19 | using threads anyway. |
19 | using threads anyway. |
20 | |
20 | |
21 | Although the module will work with in the presence of other threads, it |
21 | Although the module will work with in the presence of other threads, it |
22 | is currently not reentrant, so use appropriate locking yourself. |
22 | is currently not reentrant, so use appropriate locking yourself. |
23 | |
23 | |
24 | API NOTES |
24 | FUNCTIONS |
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25 | AIO FUNCTIONS |
25 | All the "aio_*" calls are more or less thin wrappers around the syscall |
26 | All the "aio_*" calls are more or less thin wrappers around the syscall |
26 | with the same name (sans "aio_"). The arguments are similar or |
27 | with the same name (sans "aio_"). The arguments are similar or |
27 | identical, and they all accept an additional $callback argument which |
28 | identical, and they all accept an additional $callback argument which |
28 | must be a code reference. This code reference will get called with the |
29 | must be a code reference. This code reference will get called with the |
29 | syscall return code (e.g. most syscalls return -1 on error, unlike perl, |
30 | syscall return code (e.g. most syscalls return -1 on error, unlike perl, |
… | |
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35 | |
36 | |
36 | The filenames you pass to these routines *must* be absolute. The reason |
37 | The filenames you pass to these routines *must* be absolute. The reason |
37 | is that at the time the request is being executed, the current working |
38 | is that at the time the request is being executed, the current working |
38 | directory could have changed. Alternatively, you can make sure that you |
39 | directory could have changed. Alternatively, you can make sure that you |
39 | never change the current working directory. |
40 | never change the current working directory. |
40 | |
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41 | IO::AIO::min_parallel $nthreads |
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42 | Set the minimum number of AIO threads to $nthreads. The default is |
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43 | 1, which means a single asynchronous operation can be done at one |
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44 | time (the number of outstanding operations, however, is unlimited). |
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45 | |
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46 | It is recommended to keep the number of threads low, as some Linux |
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47 | kernel versions will scale negatively with the number of threads |
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48 | (higher parallelity => MUCH higher latency). With current Linux 2.6 |
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49 | versions, 4-32 threads should be fine. |
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50 | |
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51 | Under normal circumstances you don't need to call this function, as |
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52 | this module automatically starts some threads (the exact number |
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53 | might change, and is currently 4). |
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54 | |
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55 | IO::AIO::max_parallel $nthreads |
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56 | Sets the maximum number of AIO threads to $nthreads. If more than |
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57 | the specified number of threads are currently running, kill them. |
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58 | This function blocks until the limit is reached. |
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59 | |
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60 | This module automatically runs "max_parallel 0" at program end, to |
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61 | ensure that all threads are killed and that there are no outstanding |
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62 | requests. |
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63 | |
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64 | Under normal circumstances you don't need to call this function. |
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65 | |
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66 | $oldnreqs = IO::AIO::max_outstanding $nreqs |
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67 | Sets the maximum number of outstanding requests to $nreqs. If you |
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68 | try to queue up more than this number of requests, the caller will |
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69 | block until some requests have been handled. |
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70 | |
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71 | The default is very large, so normally there is no practical limit. |
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72 | If you queue up many requests in a loop it it often improves speed |
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73 | if you set this to a relatively low number, such as 100. |
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74 | |
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75 | Under normal circumstances you don't need to call this function. |
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76 | |
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77 | $fileno = IO::AIO::poll_fileno |
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78 | Return the *request result pipe filehandle*. This filehandle must be |
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79 | polled for reading by some mechanism outside this module (e.g. Event |
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80 | or select, see below). If the pipe becomes readable you have to call |
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81 | "poll_cb" to check the results. |
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82 | |
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83 | See "poll_cb" for an example. |
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84 | |
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85 | IO::AIO::poll_cb |
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86 | Process all outstanding events on the result pipe. You have to call |
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87 | this regularly. Returns the number of events processed. Returns |
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88 | immediately when no events are outstanding. |
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89 | |
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90 | You can use Event to multiplex, e.g.: |
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91 | |
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92 | Event->io (fd => IO::AIO::poll_fileno, |
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93 | poll => 'r', async => 1, |
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94 | cb => \&IO::AIO::poll_cb); |
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95 | |
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96 | IO::AIO::poll_wait |
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97 | Wait till the result filehandle becomes ready for reading (simply |
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98 | does a select on the filehandle. This is useful if you want to |
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99 | synchronously wait for some requests to finish). |
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100 | |
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101 | See "nreqs" for an example. |
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102 | |
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103 | IO::AIO::nreqs |
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104 | Returns the number of requests currently outstanding. |
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105 | |
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106 | Example: wait till there are no outstanding requests anymore: |
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107 | |
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108 | IO::AIO::poll_wait, IO::AIO::poll_cb |
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109 | while IO::AIO::nreqs; |
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110 | |
41 | |
111 | aio_open $pathname, $flags, $mode, $callback |
42 | aio_open $pathname, $flags, $mode, $callback |
112 | Asynchronously open or create a file and call the callback with a |
43 | Asynchronously open or create a file and call the callback with a |
113 | newly created filehandle for the file. |
44 | newly created filehandle for the file. |
114 | |
45 | |
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197 | |
128 | |
198 | aio_fdatasync $fh, $callback |
129 | aio_fdatasync $fh, $callback |
199 | Asynchronously call fdatasync on the given filehandle and call the |
130 | Asynchronously call fdatasync on the given filehandle and call the |
200 | callback with the fdatasync result code. |
131 | callback with the fdatasync result code. |
201 | |
132 | |
202 | BUGS |
133 | SUPPORT FUNCTIONS |
203 | - could be optimized to use more semaphores instead of filehandles. |
134 | $fileno = IO::AIO::poll_fileno |
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135 | Return the *request result pipe filehandle*. This filehandle must be |
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136 | polled for reading by some mechanism outside this module (e.g. Event |
|
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137 | or select, see below). If the pipe becomes readable you have to call |
|
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138 | "poll_cb" to check the results. |
|
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139 | |
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140 | See "poll_cb" for an example. |
|
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141 | |
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142 | IO::AIO::poll_cb |
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143 | Process all outstanding events on the result pipe. You have to call |
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144 | this regularly. Returns the number of events processed. Returns |
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145 | immediately when no events are outstanding. |
|
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146 | |
|
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147 | You can use Event to multiplex, e.g.: |
|
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148 | |
|
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149 | Event->io (fd => IO::AIO::poll_fileno, |
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150 | poll => 'r', async => 1, |
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151 | cb => \&IO::AIO::poll_cb); |
|
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152 | |
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153 | IO::AIO::poll_wait |
|
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154 | Wait till the result filehandle becomes ready for reading (simply |
|
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155 | does a select on the filehandle. This is useful if you want to |
|
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156 | synchronously wait for some requests to finish). |
|
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157 | |
|
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158 | See "nreqs" for an example. |
|
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159 | |
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160 | IO::AIO::nreqs |
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161 | Returns the number of requests currently outstanding. |
|
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162 | |
|
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163 | Example: wait till there are no outstanding requests anymore: |
|
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164 | |
|
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165 | IO::AIO::poll_wait, IO::AIO::poll_cb |
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166 | while IO::AIO::nreqs; |
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167 | |
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168 | IO::AIO::min_parallel $nthreads |
|
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169 | Set the minimum number of AIO threads to $nthreads. The default is |
|
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170 | 1, which means a single asynchronous operation can be done at one |
|
|
171 | time (the number of outstanding operations, however, is unlimited). |
|
|
172 | |
|
|
173 | It is recommended to keep the number of threads low, as some Linux |
|
|
174 | kernel versions will scale negatively with the number of threads |
|
|
175 | (higher parallelity => MUCH higher latency). With current Linux 2.6 |
|
|
176 | versions, 4-32 threads should be fine. |
|
|
177 | |
|
|
178 | Under normal circumstances you don't need to call this function, as |
|
|
179 | this module automatically starts some threads (the exact number |
|
|
180 | might change, and is currently 4). |
|
|
181 | |
|
|
182 | IO::AIO::max_parallel $nthreads |
|
|
183 | Sets the maximum number of AIO threads to $nthreads. If more than |
|
|
184 | the specified number of threads are currently running, kill them. |
|
|
185 | This function blocks until the limit is reached. |
|
|
186 | |
|
|
187 | This module automatically runs "max_parallel 0" at program end, to |
|
|
188 | ensure that all threads are killed and that there are no outstanding |
|
|
189 | requests. |
|
|
190 | |
|
|
191 | Under normal circumstances you don't need to call this function. |
|
|
192 | |
|
|
193 | $oldnreqs = IO::AIO::max_outstanding $nreqs |
|
|
194 | Sets the maximum number of outstanding requests to $nreqs. If you |
|
|
195 | try to queue up more than this number of requests, the caller will |
|
|
196 | block until some requests have been handled. |
|
|
197 | |
|
|
198 | The default is very large, so normally there is no practical limit. |
|
|
199 | If you queue up many requests in a loop it it often improves speed |
|
|
200 | if you set this to a relatively low number, such as 100. |
|
|
201 | |
|
|
202 | Under normal circumstances you don't need to call this function. |
204 | |
203 | |
205 | SEE ALSO |
204 | SEE ALSO |
206 | Coro, Linux::AIO. |
205 | Coro, Linux::AIO. |
207 | |
206 | |
208 | AUTHOR |
207 | AUTHOR |