… | |
… | |
20 | poll => 'r', |
20 | poll => 'r', |
21 | cb => \&IO::AIO::poll_cb); |
21 | cb => \&IO::AIO::poll_cb); |
22 | |
22 | |
23 | # Glib/Gtk2 |
23 | # Glib/Gtk2 |
24 | add_watch Glib::IO IO::AIO::poll_fileno, |
24 | add_watch Glib::IO IO::AIO::poll_fileno, |
25 | in => sub { IO::AIO::poll_cb, 1 }; |
25 | in => sub { IO::AIO::poll_cb; 1 }; |
26 | |
26 | |
27 | # Tk |
27 | # Tk |
28 | Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", |
28 | Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", |
29 | readable => \&IO::AIO::poll_cb); |
29 | readable => \&IO::AIO::poll_cb); |
30 | |
30 | |
… | |
… | |
45 | currently, for example), and they would only support aio_read and |
45 | currently, for example), and they would only support aio_read and |
46 | aio_write, so the remaining functionality would have to be implemented |
46 | aio_write, so the remaining functionality would have to be implemented |
47 | using threads anyway. |
47 | using threads anyway. |
48 | |
48 | |
49 | Although the module will work with in the presence of other threads, it |
49 | Although the module will work with in the presence of other threads, it |
50 | is currently not reentrant, so use appropriate locking yourself. |
50 | is currently not reentrant, so use appropriate locking yourself, always |
|
|
51 | call "poll_cb" from within the same thread, or never call "poll_cb" (or |
|
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52 | other "aio_" functions) recursively. |
51 | |
53 | |
52 | FUNCTIONS |
54 | FUNCTIONS |
53 | AIO FUNCTIONS |
55 | AIO FUNCTIONS |
54 | All the "aio_*" calls are more or less thin wrappers around the syscall |
56 | All the "aio_*" calls are more or less thin wrappers around the syscall |
55 | with the same name (sans "aio_"). The arguments are similar or |
57 | with the same name (sans "aio_"). The arguments are similar or |
… | |
… | |
57 | argument which must be a code reference. This code reference will get |
59 | argument which must be a code reference. This code reference will get |
58 | called with the syscall return code (e.g. most syscalls return -1 on |
60 | called with the syscall return code (e.g. most syscalls return -1 on |
59 | error, unlike perl, which usually delivers "false") as it's sole |
61 | error, unlike perl, which usually delivers "false") as it's sole |
60 | argument when the given syscall has been executed asynchronously. |
62 | argument when the given syscall has been executed asynchronously. |
61 | |
63 | |
62 | All functions that expect a filehandle will also accept a file |
64 | All functions expecting a filehandle keep a copy of the filehandle |
63 | descriptor. |
65 | internally until the request has finished. |
64 | |
66 | |
65 | The filenames you pass to these routines *must* be absolute. The reason |
67 | The pathnames you pass to these routines *must* be absolute and encoded |
66 | is that at the time the request is being executed, the current working |
68 | in byte form. The reason for the former is that at the time the request |
67 | directory could have changed. Alternatively, you can make sure that you |
69 | is being executed, the current working directory could have changed. |
68 | never change the current working directory. |
70 | Alternatively, you can make sure that you never change the current |
|
|
71 | working directory. |
69 | |
72 | |
|
|
73 | To encode pathnames to byte form, either make sure you either: a) always |
|
|
74 | pass in filenames you got from outside (command line, readdir etc.), b) |
|
|
75 | are ASCII or ISO 8859-1, c) use the Encode module and encode your |
|
|
76 | pathnames to the locale (or other) encoding in effect in the user |
|
|
77 | environment, d) use Glib::filename_from_unicode on unicode filenames or |
|
|
78 | e) use something else. |
|
|
79 | |
70 | aio_open $pathname, $flags, $mode, $callback |
80 | aio_open $pathname, $flags, $mode, $callback->($fh) |
71 | Asynchronously open or create a file and call the callback with a |
81 | Asynchronously open or create a file and call the callback with a |
72 | newly created filehandle for the file. |
82 | newly created filehandle for the file. |
73 | |
83 | |
74 | The pathname passed to "aio_open" must be absolute. See API NOTES, |
84 | The pathname passed to "aio_open" must be absolute. See API NOTES, |
75 | above, for an explanation. |
85 | above, for an explanation. |
76 | |
86 | |
77 | The $mode argument is a bitmask. See the "Fcntl" module for a list. |
87 | The $flags argument is a bitmask. See the "Fcntl" module for a list. |
78 | They are the same as used in "sysopen". |
88 | They are the same as used by "sysopen". |
|
|
89 | |
|
|
90 | Likewise, $mode specifies the mode of the newly created file, if it |
|
|
91 | didn't exist and "O_CREAT" has been given, just like perl's |
|
|
92 | "sysopen", except that it is mandatory (i.e. use 0 if you don't |
|
|
93 | create new files, and 0666 or 0777 if you do). |
79 | |
94 | |
80 | Example: |
95 | Example: |
81 | |
96 | |
82 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
97 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
83 | if ($_[0]) { |
98 | if ($_[0]) { |
… | |
… | |
86 | } else { |
101 | } else { |
87 | die "open failed: $!\n"; |
102 | die "open failed: $!\n"; |
88 | } |
103 | } |
89 | }; |
104 | }; |
90 | |
105 | |
91 | aio_close $fh, $callback |
106 | aio_close $fh, $callback->($status) |
92 | Asynchronously close a file and call the callback with the result |
107 | Asynchronously close a file and call the callback with the result |
93 | code. *WARNING:* although accepted, you should not pass in a perl |
108 | code. *WARNING:* although accepted, you should not pass in a perl |
94 | filehandle here, as perl will likely close the file descriptor |
109 | filehandle here, as perl will likely close the file descriptor |
95 | itself when the filehandle is destroyed. Normally, you can safely |
110 | another time when the filehandle is destroyed. Normally, you can |
96 | call perls "close" or just let filehandles go out of scope. |
111 | safely call perls "close" or just let filehandles go out of scope. |
97 | |
112 | |
|
|
113 | This is supposed to be a bug in the API, so that might change. It's |
|
|
114 | therefore best to avoid this function. |
|
|
115 | |
98 | aio_read $fh,$offset,$length, $data,$dataoffset,$callback |
116 | aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
99 | aio_write $fh,$offset,$length, $data,$dataoffset,$callback |
117 | aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
100 | Reads or writes "length" bytes from the specified "fh" and "offset" |
118 | Reads or writes "length" bytes from the specified "fh" and "offset" |
101 | into the scalar given by "data" and offset "dataoffset" and calls |
119 | into the scalar given by "data" and offset "dataoffset" and calls |
102 | the callback without the actual number of bytes read (or -1 on |
120 | the callback without the actual number of bytes read (or -1 on |
103 | error, just like the syscall). |
121 | error, just like the syscall). |
104 | |
122 | |
|
|
123 | The $data scalar *MUST NOT* be modified in any way while the request |
|
|
124 | is outstanding. Modifying it can result in segfaults or WW3 (if the |
|
|
125 | necessary/optional hardware is installed). |
|
|
126 | |
105 | Example: Read 15 bytes at offset 7 into scalar $buffer, starting at |
127 | Example: Read 15 bytes at offset 7 into scalar $buffer, starting at |
106 | offset 0 within the scalar: |
128 | offset 0 within the scalar: |
107 | |
129 | |
108 | aio_read $fh, 7, 15, $buffer, 0, sub { |
130 | aio_read $fh, 7, 15, $buffer, 0, sub { |
109 | $_[0] > 0 or die "read error: $!"; |
131 | $_[0] > 0 or die "read error: $!"; |
110 | print "read $_[0] bytes: <$buffer>\n"; |
132 | print "read $_[0] bytes: <$buffer>\n"; |
111 | }; |
133 | }; |
112 | |
134 | |
|
|
135 | aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
|
|
136 | Tries to copy $length bytes from $in_fh to $out_fh. It starts |
|
|
137 | reading at byte offset $in_offset, and starts writing at the current |
|
|
138 | file offset of $out_fh. Because of that, it is not safe to issue |
|
|
139 | more than one "aio_sendfile" per $out_fh, as they will interfere |
|
|
140 | with each other. |
|
|
141 | |
|
|
142 | This call tries to make use of a native "sendfile" syscall to |
|
|
143 | provide zero-copy operation. For this to work, $out_fh should refer |
|
|
144 | to a socket, and $in_fh should refer to mmap'able file. |
|
|
145 | |
|
|
146 | If the native sendfile call fails or is not implemented, it will be |
|
|
147 | emulated, so you can call "aio_sendfile" on any type of filehandle |
|
|
148 | regardless of the limitations of the operating system. |
|
|
149 | |
|
|
150 | Please note, however, that "aio_sendfile" can read more bytes from |
|
|
151 | $in_fh than are written, and there is no way to find out how many |
|
|
152 | bytes have been read from "aio_sendfile" alone, as "aio_sendfile" |
|
|
153 | only provides the number of bytes written to $out_fh. Only if the |
|
|
154 | result value equals $length one can assume that $length bytes have |
|
|
155 | been read. |
|
|
156 | |
113 | aio_readahead $fh,$offset,$length, $callback |
157 | aio_readahead $fh,$offset,$length, $callback->($retval) |
114 | Asynchronously reads the specified byte range into the page cache, |
|
|
115 | using the "readahead" syscall. If that syscall doesn't exist (likely |
|
|
116 | if your OS isn't Linux) the status will be -1 and $! is set to |
|
|
117 | ENOSYS. |
|
|
118 | |
|
|
119 | readahead() populates the page cache with data from a file so that |
158 | "aio_readahead" populates the page cache with data from a file so |
120 | subsequent reads from that file will not block on disk I/O. The |
159 | that subsequent reads from that file will not block on disk I/O. The |
121 | $offset argument specifies the starting point from which data is to |
160 | $offset argument specifies the starting point from which data is to |
122 | be read and $length specifies the number of bytes to be read. I/O is |
161 | be read and $length specifies the number of bytes to be read. I/O is |
123 | performed in whole pages, so that offset is effectively rounded down |
162 | performed in whole pages, so that offset is effectively rounded down |
124 | to a page boundary and bytes are read up to the next page boundary |
163 | to a page boundary and bytes are read up to the next page boundary |
125 | greater than or equal to (off-set+length). aio_readahead() does not |
164 | greater than or equal to (off-set+length). "aio_readahead" does not |
126 | read beyond the end of the file. The current file offset of the file |
165 | read beyond the end of the file. The current file offset of the file |
127 | is left unchanged. |
166 | is left unchanged. |
128 | |
167 | |
|
|
168 | If that syscall doesn't exist (likely if your OS isn't Linux) it |
|
|
169 | will be emulated by simply reading the data, which would have a |
|
|
170 | similar effect. |
|
|
171 | |
129 | aio_stat $fh_or_path, $callback |
172 | aio_stat $fh_or_path, $callback->($status) |
130 | aio_lstat $fh, $callback |
173 | aio_lstat $fh, $callback->($status) |
131 | Works like perl's "stat" or "lstat" in void context. The callback |
174 | Works like perl's "stat" or "lstat" in void context. The callback |
132 | will be called after the stat and the results will be available |
175 | will be called after the stat and the results will be available |
133 | using "stat _" or "-s _" etc... |
176 | using "stat _" or "-s _" etc... |
134 | |
177 | |
135 | The pathname passed to "aio_stat" must be absolute. See API NOTES, |
178 | The pathname passed to "aio_stat" must be absolute. See API NOTES, |
… | |
… | |
145 | aio_stat "/etc/passwd", sub { |
188 | aio_stat "/etc/passwd", sub { |
146 | $_[0] and die "stat failed: $!"; |
189 | $_[0] and die "stat failed: $!"; |
147 | print "size is ", -s _, "\n"; |
190 | print "size is ", -s _, "\n"; |
148 | }; |
191 | }; |
149 | |
192 | |
150 | aio_unlink $pathname, $callback |
193 | aio_unlink $pathname, $callback->($status) |
151 | Asynchronously unlink (delete) a file and call the callback with the |
194 | Asynchronously unlink (delete) a file and call the callback with the |
152 | result code. |
195 | result code. |
153 | |
196 | |
|
|
197 | aio_rmdir $pathname, $callback->($status) |
|
|
198 | Asynchronously rmdir (delete) a directory and call the callback with |
|
|
199 | the result code. |
|
|
200 | |
|
|
201 | aio_readdir $pathname $callback->($entries) |
|
|
202 | Unlike the POSIX call of the same name, "aio_readdir" reads an |
|
|
203 | entire directory (i.e. opendir + readdir + closedir). The entries |
|
|
204 | will not be sorted, and will NOT include the "." and ".." entries. |
|
|
205 | |
|
|
206 | The callback a single argument which is either "undef" or an |
|
|
207 | array-ref with the filenames. |
|
|
208 | |
|
|
209 | aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
|
|
210 | Scans a directory (similar to "aio_readdir") and tries to separate |
|
|
211 | the entries of directory $path into two sets of names, ones you can |
|
|
212 | recurse into (directories), and ones you cannot recurse into |
|
|
213 | (everything else). |
|
|
214 | |
|
|
215 | "aio_scandir" is a composite request that consists of many |
|
|
216 | aio-primitives. $maxreq specifies the maximum number of outstanding |
|
|
217 | aio requests that this function generates. If it is "<= 0", then a |
|
|
218 | suitable default will be chosen (currently 8). |
|
|
219 | |
|
|
220 | On error, the callback is called without arguments, otherwise it |
|
|
221 | receives two array-refs with path-relative entry names. |
|
|
222 | |
|
|
223 | Example: |
|
|
224 | |
|
|
225 | aio_scandir $dir, 0, sub { |
|
|
226 | my ($dirs, $nondirs) = @_; |
|
|
227 | print "real directories: @$dirs\n"; |
|
|
228 | print "everything else: @$nondirs\n"; |
|
|
229 | }; |
|
|
230 | |
|
|
231 | Implementation notes. |
|
|
232 | |
|
|
233 | The "aio_readdir" cannot be avoided, but "stat()"'ing every entry |
|
|
234 | can. |
|
|
235 | |
|
|
236 | After reading the directory, the modification time, size etc. of the |
|
|
237 | directory before and after the readdir is checked, and if they |
|
|
238 | match, the link count will be used to decide how many entries are |
|
|
239 | directories (if >= 2). Otherwise, no knowledge of the number of |
|
|
240 | subdirectories will be assumed. |
|
|
241 | |
|
|
242 | Then entires will be sorted into likely directories (everything |
|
|
243 | without a non-initial dot) and likely non-directories (everything |
|
|
244 | else). Then every entry + "/." will be "stat"'ed, likely directories |
|
|
245 | first. This is often faster because filesystems might detect the |
|
|
246 | type of the entry without reading the inode data (e.g. ext2s |
|
|
247 | filetype feature). If that succeeds, it assumes that the entry is a |
|
|
248 | directory or a symlink to directory (which will be checked |
|
|
249 | seperately). |
|
|
250 | |
|
|
251 | If the known number of directories has been reached, the rest of the |
|
|
252 | entries is assumed to be non-directories. |
|
|
253 | |
154 | aio_fsync $fh, $callback |
254 | aio_fsync $fh, $callback->($status) |
155 | Asynchronously call fsync on the given filehandle and call the |
255 | Asynchronously call fsync on the given filehandle and call the |
156 | callback with the fsync result code. |
256 | callback with the fsync result code. |
157 | |
257 | |
158 | aio_fdatasync $fh, $callback |
258 | aio_fdatasync $fh, $callback->($status) |
159 | Asynchronously call fdatasync on the given filehandle and call the |
259 | Asynchronously call fdatasync on the given filehandle and call the |
160 | callback with the fdatasync result code. |
260 | callback with the fdatasync result code. |
161 | |
261 | |
|
|
262 | If this call isn't available because your OS lacks it or it couldn't |
|
|
263 | be detected, it will be emulated by calling "fsync" instead. |
|
|
264 | |
162 | SUPPORT FUNCTIONS |
265 | SUPPORT FUNCTIONS |
163 | $fileno = IO::AIO::poll_fileno |
266 | $fileno = IO::AIO::poll_fileno |
164 | Return the *request result pipe filehandle*. This filehandle must be |
267 | Return the *request result pipe file descriptor*. This filehandle |
165 | polled for reading by some mechanism outside this module (e.g. Event |
268 | must be polled for reading by some mechanism outside this module |
166 | or select, see below). If the pipe becomes readable you have to call |
269 | (e.g. Event or select, see below or the SYNOPSIS). If the pipe |
167 | "poll_cb" to check the results. |
270 | becomes readable you have to call "poll_cb" to check the results. |
168 | |
271 | |
169 | See "poll_cb" for an example. |
272 | See "poll_cb" for an example. |
170 | |
273 | |
171 | IO::AIO::poll_cb |
274 | IO::AIO::poll_cb |
172 | Process all outstanding events on the result pipe. You have to call |
275 | Process all outstanding events on the result pipe. You have to call |
173 | this regularly. Returns the number of events processed. Returns |
276 | this regularly. Returns the number of events processed. Returns |
174 | immediately when no events are outstanding. |
277 | immediately when no events are outstanding. |
175 | |
278 | |
176 | You can use Event to multiplex, e.g.: |
279 | Example: Install an Event watcher that automatically calls |
|
|
280 | IO::AIO::poll_cb with high priority: |
177 | |
281 | |
178 | Event->io (fd => IO::AIO::poll_fileno, |
282 | Event->io (fd => IO::AIO::poll_fileno, |
179 | poll => 'r', async => 1, |
283 | poll => 'r', async => 1, |
180 | cb => \&IO::AIO::poll_cb); |
284 | cb => \&IO::AIO::poll_cb); |
181 | |
285 | |
182 | IO::AIO::poll_wait |
286 | IO::AIO::poll_wait |
183 | Wait till the result filehandle becomes ready for reading (simply |
287 | Wait till the result filehandle becomes ready for reading (simply |
184 | does a select on the filehandle. This is useful if you want to |
288 | does a "select" on the filehandle. This is useful if you want to |
185 | synchronously wait for some requests to finish). |
289 | synchronously wait for some requests to finish). |
186 | |
290 | |
187 | See "nreqs" for an example. |
291 | See "nreqs" for an example. |
188 | |
292 | |
189 | IO::AIO::nreqs |
293 | IO::AIO::nreqs |
190 | Returns the number of requests currently outstanding. |
294 | Returns the number of requests currently outstanding (i.e. for which |
|
|
295 | their callback has not been invoked yet). |
191 | |
296 | |
192 | Example: wait till there are no outstanding requests anymore: |
297 | Example: wait till there are no outstanding requests anymore: |
193 | |
298 | |
194 | IO::AIO::poll_wait, IO::AIO::poll_cb |
299 | IO::AIO::poll_wait, IO::AIO::poll_cb |
195 | while IO::AIO::nreqs; |
300 | while IO::AIO::nreqs; |
… | |
… | |
209 | |
314 | |
210 | IO::AIO::poll_wait, IO::AIO::poll_cb |
315 | IO::AIO::poll_wait, IO::AIO::poll_cb |
211 | if IO::AIO::nreqs; |
316 | if IO::AIO::nreqs; |
212 | |
317 | |
213 | IO::AIO::min_parallel $nthreads |
318 | IO::AIO::min_parallel $nthreads |
214 | Set the minimum number of AIO threads to $nthreads. The default is |
319 | Set the minimum number of AIO threads to $nthreads. The current |
215 | 1, which means a single asynchronous operation can be done at one |
320 | default is 4, which means four asynchronous operations can be done |
216 | time (the number of outstanding operations, however, is unlimited). |
321 | at one time (the number of outstanding operations, however, is |
|
|
322 | unlimited). |
|
|
323 | |
|
|
324 | IO::AIO starts threads only on demand, when an AIO request is queued |
|
|
325 | and no free thread exists. |
217 | |
326 | |
218 | It is recommended to keep the number of threads low, as some Linux |
327 | It is recommended to keep the number of threads low, as some Linux |
219 | kernel versions will scale negatively with the number of threads |
328 | kernel versions will scale negatively with the number of threads |
220 | (higher parallelity => MUCH higher latency). With current Linux 2.6 |
329 | (higher parallelity => MUCH higher latency). With current Linux 2.6 |
221 | versions, 4-32 threads should be fine. |
330 | versions, 4-32 threads should be fine. |
222 | |
331 | |
223 | Under normal circumstances you don't need to call this function, as |
332 | Under most circumstances you don't need to call this function, as |
224 | this module automatically starts some threads (the exact number |
333 | the module selects a default that is suitable for low to moderate |
225 | might change, and is currently 4). |
334 | load. |
226 | |
335 | |
227 | IO::AIO::max_parallel $nthreads |
336 | IO::AIO::max_parallel $nthreads |
228 | Sets the maximum number of AIO threads to $nthreads. If more than |
337 | Sets the maximum number of AIO threads to $nthreads. If more than |
229 | the specified number of threads are currently running, kill them. |
338 | the specified number of threads are currently running, this function |
230 | This function blocks until the limit is reached. |
339 | kills them. This function blocks until the limit is reached. |
|
|
340 | |
|
|
341 | While $nthreads are zero, aio requests get queued but not executed |
|
|
342 | until the number of threads has been increased again. |
231 | |
343 | |
232 | This module automatically runs "max_parallel 0" at program end, to |
344 | This module automatically runs "max_parallel 0" at program end, to |
233 | ensure that all threads are killed and that there are no outstanding |
345 | ensure that all threads are killed and that there are no outstanding |
234 | requests. |
346 | requests. |
235 | |
347 | |
… | |
… | |
239 | Sets the maximum number of outstanding requests to $nreqs. If you |
351 | Sets the maximum number of outstanding requests to $nreqs. If you |
240 | try to queue up more than this number of requests, the caller will |
352 | try to queue up more than this number of requests, the caller will |
241 | block until some requests have been handled. |
353 | block until some requests have been handled. |
242 | |
354 | |
243 | The default is very large, so normally there is no practical limit. |
355 | The default is very large, so normally there is no practical limit. |
244 | If you queue up many requests in a loop it it often improves speed |
356 | If you queue up many requests in a loop it often improves speed if |
245 | if you set this to a relatively low number, such as 100. |
357 | you set this to a relatively low number, such as 100. |
246 | |
358 | |
247 | Under normal circumstances you don't need to call this function. |
359 | Under normal circumstances you don't need to call this function. |
|
|
360 | |
|
|
361 | FORK BEHAVIOUR |
|
|
362 | Before the fork, IO::AIO enters a quiescent state where no requests can |
|
|
363 | be added in other threads and no results will be processed. After the |
|
|
364 | fork the parent simply leaves the quiescent state and continues |
|
|
365 | request/result processing, while the child clears the request/result |
|
|
366 | queue (so the requests started before the fork will only be handled in |
|
|
367 | the parent). Threats will be started on demand until the limit ste in |
|
|
368 | the parent process has been reached again. |
248 | |
369 | |
249 | SEE ALSO |
370 | SEE ALSO |
250 | Coro, Linux::AIO. |
371 | Coro, Linux::AIO. |
251 | |
372 | |
252 | AUTHOR |
373 | AUTHOR |