… | |
… | |
168 | aio_unlink $pathname, $callback->($status) |
168 | aio_unlink $pathname, $callback->($status) |
169 | aio_mknod $path, $mode, $dev, $callback->($status) |
169 | aio_mknod $path, $mode, $dev, $callback->($status) |
170 | aio_link $srcpath, $dstpath, $callback->($status) |
170 | aio_link $srcpath, $dstpath, $callback->($status) |
171 | aio_symlink $srcpath, $dstpath, $callback->($status) |
171 | aio_symlink $srcpath, $dstpath, $callback->($status) |
172 | aio_readlink $path, $callback->($link) |
172 | aio_readlink $path, $callback->($link) |
|
|
173 | aio_realpath $path, $callback->($link) |
173 | aio_rename $srcpath, $dstpath, $callback->($status) |
174 | aio_rename $srcpath, $dstpath, $callback->($status) |
174 | aio_mkdir $pathname, $mode, $callback->($status) |
175 | aio_mkdir $pathname, $mode, $callback->($status) |
175 | aio_rmdir $pathname, $callback->($status) |
176 | aio_rmdir $pathname, $callback->($status) |
176 | aio_readdir $pathname, $callback->($entries) |
177 | aio_readdir $pathname, $callback->($entries) |
177 | aio_readdirx $pathname, $flags, $callback->($entries, $flags) |
178 | aio_readdirx $pathname, $flags, $callback->($entries, $flags) |
… | |
… | |
367 | aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
368 | aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
368 | Tries to copy $length bytes from $in_fh to $out_fh. It starts |
369 | Tries to copy $length bytes from $in_fh to $out_fh. It starts |
369 | reading at byte offset $in_offset, and starts writing at the current |
370 | reading at byte offset $in_offset, and starts writing at the current |
370 | file offset of $out_fh. Because of that, it is not safe to issue |
371 | file offset of $out_fh. Because of that, it is not safe to issue |
371 | more than one "aio_sendfile" per $out_fh, as they will interfere |
372 | more than one "aio_sendfile" per $out_fh, as they will interfere |
372 | with each other. |
373 | with each other. The same $in_fh works fine though, as this function |
|
|
374 | does not move or use the file offset of $in_fh. |
373 | |
375 | |
374 | Please note that "aio_sendfile" can read more bytes from $in_fh than |
376 | Please note that "aio_sendfile" can read more bytes from $in_fh than |
375 | are written, and there is no way to find out how many bytes have |
377 | are written, and there is no way to find out how many more bytes |
376 | been read from "aio_sendfile" alone, as "aio_sendfile" only provides |
378 | have been read from "aio_sendfile" alone, as "aio_sendfile" only |
377 | the number of bytes written to $out_fh. Only if the result value |
379 | provides the number of bytes written to $out_fh. Only if the result |
378 | equals $length one can assume that $length bytes have been read. |
380 | value equals $length one can assume that $length bytes have been |
|
|
381 | read. |
379 | |
382 | |
380 | Unlike with other "aio_" functions, it makes a lot of sense to use |
383 | Unlike with other "aio_" functions, it makes a lot of sense to use |
381 | "aio_sendfile" on non-blocking sockets, as long as one end |
384 | "aio_sendfile" on non-blocking sockets, as long as one end |
382 | (typically the $in_fh) is a file - the file I/O will then be |
385 | (typically the $in_fh) is a file - the file I/O will then be |
383 | asynchronous, while the socket I/O will be non-blocking. Note, |
386 | asynchronous, while the socket I/O will be non-blocking. Note, |
384 | however, that you can run into a trap where "aio_sendfile" reads |
387 | however, that you can run into a trap where "aio_sendfile" reads |
385 | some data with readahead, then fails to write all data, and when the |
388 | some data with readahead, then fails to write all data, and when the |
386 | socket is ready the next time, the data in the cache is already |
389 | socket is ready the next time, the data in the cache is already |
387 | lost, forcing "aio_sendfile" to again hit the disk. Explicit |
390 | lost, forcing "aio_sendfile" to again hit the disk. Explicit |
388 | "aio_read" + "aio_write" let's you control resource usage much |
391 | "aio_read" + "aio_write" let's you better control resource usage. |
389 | better. |
|
|
390 | |
392 | |
391 | This call tries to make use of a native "sendfile" syscall to |
393 | This call tries to make use of a native "sendfile"-like syscall to |
392 | provide zero-copy operation. For this to work, $out_fh should refer |
394 | provide zero-copy operation. For this to work, $out_fh should refer |
393 | to a socket, and $in_fh should refer to an mmap'able file. |
395 | to a socket, and $in_fh should refer to an mmap'able file. |
394 | |
396 | |
395 | If a native sendfile cannot be found or it fails with "ENOSYS", |
397 | If a native sendfile cannot be found or it fails with "ENOSYS", |
396 | "ENOTSUP", "EOPNOTSUPP", "EAFNOSUPPORT", "EPROTOTYPE" or "ENOTSOCK", |
398 | "EINVAL", "ENOTSUP", "EOPNOTSUPP", "EAFNOSUPPORT", "EPROTOTYPE" or |
397 | it will be emulated, so you can call "aio_sendfile" on any type of |
399 | "ENOTSOCK", it will be emulated, so you can call "aio_sendfile" on |
398 | filehandle regardless of the limitations of the operating system. |
400 | any type of filehandle regardless of the limitations of the |
|
|
401 | operating system. |
|
|
402 | |
|
|
403 | As native sendfile syscalls (as practically any non-POSIX interface |
|
|
404 | hacked together in a hurry to improve benchmark numbers) tend to be |
|
|
405 | rather buggy on many systems, this implementation tries to work |
|
|
406 | around some known bugs in Linux and FreeBSD kernels (probably |
|
|
407 | others, too), but that might fail, so you really really should check |
|
|
408 | the return value of "aio_sendfile" - fewre bytes than expected might |
|
|
409 | have been transferred. |
399 | |
410 | |
400 | aio_readahead $fh,$offset,$length, $callback->($retval) |
411 | aio_readahead $fh,$offset,$length, $callback->($retval) |
401 | "aio_readahead" populates the page cache with data from a file so |
412 | "aio_readahead" populates the page cache with data from a file so |
402 | that subsequent reads from that file will not block on disk I/O. The |
413 | that subsequent reads from that file will not block on disk I/O. The |
403 | $offset argument specifies the starting point from which data is to |
414 | $offset argument specifies the starting point from which data is to |
… | |
… | |
547 | aio_readlink $path, $callback->($link) |
558 | aio_readlink $path, $callback->($link) |
548 | Asynchronously read the symlink specified by $path and pass it to |
559 | Asynchronously read the symlink specified by $path and pass it to |
549 | the callback. If an error occurs, nothing or undef gets passed to |
560 | the callback. If an error occurs, nothing or undef gets passed to |
550 | the callback. |
561 | the callback. |
551 | |
562 | |
|
|
563 | aio_realpath $path, $callback->($path) |
|
|
564 | Asynchronously make the path absolute and resolve any symlinks in |
|
|
565 | $path. The resulting path only consists of directories (Same as |
|
|
566 | Cwd::realpath). |
|
|
567 | |
|
|
568 | This request can be used to get the absolute path of the current |
|
|
569 | working directory by passing it a path of . (a single dot). |
|
|
570 | |
552 | aio_rename $srcpath, $dstpath, $callback->($status) |
571 | aio_rename $srcpath, $dstpath, $callback->($status) |
553 | Asynchronously rename the object at $srcpath to $dstpath, just as |
572 | Asynchronously rename the object at $srcpath to $dstpath, just as |
554 | rename(2) and call the callback with the result code. |
573 | rename(2) and call the callback with the result code. |
555 | |
574 | |
556 | aio_mkdir $pathname, $mode, $callback->($status) |
575 | aio_mkdir $pathname, $mode, $callback->($status) |
… | |
… | |
1170 | IO::AIO::idle_timeout $seconds |
1189 | IO::AIO::idle_timeout $seconds |
1171 | Sets the minimum idle timeout (default 10) after which worker |
1190 | Sets the minimum idle timeout (default 10) after which worker |
1172 | threads are allowed to exit. SEe "IO::AIO::max_idle". |
1191 | threads are allowed to exit. SEe "IO::AIO::max_idle". |
1173 | |
1192 | |
1174 | IO::AIO::max_outstanding $maxreqs |
1193 | IO::AIO::max_outstanding $maxreqs |
|
|
1194 | Sets the maximum number of outstanding requests to $nreqs. If you do |
|
|
1195 | queue up more than this number of requests, the next call to |
|
|
1196 | "IO::AIO::poll_cb" (and other functions calling "poll_cb", such as |
|
|
1197 | "IO::AIO::flush" or "IO::AIO::poll") will block until the limit is |
|
|
1198 | no longer exceeded. |
|
|
1199 | |
|
|
1200 | In other words, this setting does not enforce a queue limit, but can |
|
|
1201 | be used to make poll functions block if the limit is exceeded. |
|
|
1202 | |
1175 | This is a very bad function to use in interactive programs because |
1203 | This is a very bad function to use in interactive programs because |
1176 | it blocks, and a bad way to reduce concurrency because it is |
1204 | it blocks, and a bad way to reduce concurrency because it is |
1177 | inexact: Better use an "aio_group" together with a feed callback. |
1205 | inexact: Better use an "aio_group" together with a feed callback. |
1178 | |
1206 | |
1179 | Sets the maximum number of outstanding requests to $nreqs. If you do |
1207 | It's main use is in scripts without an event loop - when you want to |
1180 | queue up more than this number of requests, the next call to the |
1208 | stat a lot of files, you can write somehting like this: |
1181 | "poll_cb" (and "poll_some" and other functions calling "poll_cb") |
|
|
1182 | function will block until the limit is no longer exceeded. |
|
|
1183 | |
1209 | |
1184 | The default value is very large, so there is no practical limit on |
1210 | IO::AIO::max_outstanding 32; |
|
|
1211 | |
|
|
1212 | for my $path (...) { |
|
|
1213 | aio_stat $path , ...; |
|
|
1214 | IO::AIO::poll_cb; |
|
|
1215 | } |
|
|
1216 | |
|
|
1217 | IO::AIO::flush; |
|
|
1218 | |
|
|
1219 | The call to "poll_cb" inside the loop will normally return |
|
|
1220 | instantly, but as soon as more thna 32 reqeusts are in-flight, it |
|
|
1221 | will block until some requests have been handled. This keeps the |
|
|
1222 | loop from pushing a large number of "aio_stat" requests onto the |
|
|
1223 | queue. |
|
|
1224 | |
|
|
1225 | The default value for "max_outstanding" is very large, so there is |
1185 | the number of outstanding requests. |
1226 | no practical limit on the number of outstanding requests. |
1186 | |
|
|
1187 | You can still queue as many requests as you want. Therefore, |
|
|
1188 | "max_outstanding" is mainly useful in simple scripts (with low |
|
|
1189 | values) or as a stop gap to shield against fatal memory overflow |
|
|
1190 | (with large values). |
|
|
1191 | |
1227 | |
1192 | STATISTICAL INFORMATION |
1228 | STATISTICAL INFORMATION |
1193 | IO::AIO::nreqs |
1229 | IO::AIO::nreqs |
1194 | Returns the number of requests currently in the ready, execute or |
1230 | Returns the number of requests currently in the ready, execute or |
1195 | pending states (i.e. for which their callback has not been invoked |
1231 | pending states (i.e. for which their callback has not been invoked |
… | |
… | |
1341 | # Danga::Socket integration |
1377 | # Danga::Socket integration |
1342 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
1378 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
1343 | \&IO::AIO::poll_cb); |
1379 | \&IO::AIO::poll_cb); |
1344 | |
1380 | |
1345 | FORK BEHAVIOUR |
1381 | FORK BEHAVIOUR |
1346 | This module should do "the right thing" when the process using it forks: |
1382 | Usage of pthreads in a program changes the semantics of fork |
|
|
1383 | considerably. Specifically, only async-safe functions can be called |
|
|
1384 | after fork. Perl doesn't know about this, so in general, you cannot call |
|
|
1385 | fork with defined behaviour in perl if pthreads are involved. IO::AIO |
|
|
1386 | uses pthreads, so this applies, but many other extensions and (for |
|
|
1387 | inexplicable reasons) perl itself often is linked against pthreads, so |
|
|
1388 | this limitation applies to quite a lot of perls. |
1347 | |
1389 | |
1348 | Before the fork, IO::AIO enters a quiescent state where no requests can |
1390 | This module no longer tries to fight your OS, or POSIX. That means |
1349 | be added in other threads and no results will be processed. After the |
1391 | IO::AIO only works in the process that loaded it. Forking is fully |
1350 | fork the parent simply leaves the quiescent state and continues |
1392 | supported, but using IO::AIO in the child is not. |
1351 | request/result processing, while the child frees the request/result |
|
|
1352 | queue (so that the requests started before the fork will only be handled |
|
|
1353 | in the parent). Threads will be started on demand until the limit set in |
|
|
1354 | the parent process has been reached again. |
|
|
1355 | |
1393 | |
1356 | In short: the parent will, after a short pause, continue as if fork had |
1394 | You might get around by not *using* IO::AIO before (or after) forking. |
1357 | not been called, while the child will act as if IO::AIO has not been |
1395 | You could also try to call the IO::AIO::reinit function in the child: |
1358 | used yet. |
1396 | |
|
|
1397 | IO::AIO::reinit |
|
|
1398 | Abondons all current requests and I/O threads and simply |
|
|
1399 | reinitialises all data structures. This is not an operation |
|
|
1400 | suppported by any standards, but happens to work on GNU/Linux and |
|
|
1401 | some newer BSD systems. |
|
|
1402 | |
|
|
1403 | The only reasonable use for this function is to call it after |
|
|
1404 | forking, if "IO::AIO" was used in the parent. Calling it while |
|
|
1405 | IO::AIO is active in the process will result in undefined behaviour. |
|
|
1406 | Calling it at any time will also result in any undefined (by POSIX) |
|
|
1407 | behaviour. |
1359 | |
1408 | |
1360 | MEMORY USAGE |
1409 | MEMORY USAGE |
1361 | Per-request usage: |
1410 | Per-request usage: |
1362 | |
1411 | |
1363 | Each aio request uses - depending on your architecture - around 100-200 |
1412 | Each aio request uses - depending on your architecture - around 100-200 |