… | |
… | |
21 | min_parallel from the same thread that loaded this module. |
21 | min_parallel from the same thread that loaded this module. |
22 | |
22 | |
23 | Although the module will work with in the presence of other threads, it |
23 | Although the module will work with in the presence of other threads, it |
24 | is not reentrant, so use appropriate locking yourself. |
24 | is not reentrant, so use appropriate locking yourself. |
25 | |
25 | |
|
|
26 | API NOTES |
|
|
27 | All the "aio_*" calls are more or less thin wrappers around the syscall |
|
|
28 | with the same name (sans "aio_"). The arguments are similar or |
|
|
29 | identical, and they all accept an additional $callback argument which |
|
|
30 | must be a code reference. This code reference will get called with the |
|
|
31 | syscall return code (e.g. most syscalls return -1 on error, unlike perl, |
|
|
32 | which usually delivers "false") as it's sole argument when the given |
|
|
33 | syscall has been executed asynchronously. |
|
|
34 | |
|
|
35 | All functions that expect a filehandle will also accept a file |
|
|
36 | descriptor. |
|
|
37 | |
26 | Linux::AIO::min_parallel $nthreads |
38 | Linux::AIO::min_parallel $nthreads |
27 | Set the minimum number of AIO threads to $nthreads. The default is |
39 | Set the minimum number of AIO threads to $nthreads. The default is |
28 | 1, which means a single asynchronous operation can be done at one |
40 | 1, which means a single asynchronous operation can be done at one |
29 | time (the number of outstanding operations, however, is unlimited). |
41 | time (the number of outstanding operations, however, is unlimited). |
30 | |
42 | |
31 | It is recommended to keep the number of threads low, as some linux |
43 | It is recommended to keep the number of threads low, as some linux |
32 | kernel versions will scale negatively with the number of threads |
44 | kernel versions will scale negatively with the number of threads |
33 | (higher parallelity => MUCH higher latency). |
45 | (higher parallelity => MUCH higher latency). |
|
|
46 | |
|
|
47 | Under normal circumstances you don't need to call this function, as |
|
|
48 | this module automatically starts a single async thread. |
34 | |
49 | |
35 | Linux::AIO::max_parallel $nthreads |
50 | Linux::AIO::max_parallel $nthreads |
36 | Sets the maximum number of AIO threads to $nthreads. If more than |
51 | Sets the maximum number of AIO threads to $nthreads. If more than |
37 | the specified number of threads are currently running, kill them. |
52 | the specified number of threads are currently running, kill them. |
38 | This function blocks until the limit is reached. |
53 | This function blocks until the limit is reached. |
39 | |
54 | |
40 | This module automatically runs "max_parallel 0" at program end, to |
55 | This module automatically runs "max_parallel 0" at program end, to |
41 | ensure that all threads are killed and that there are no outstanding |
56 | ensure that all threads are killed and that there are no outstanding |
42 | requests. |
57 | requests. |
43 | |
58 | |
|
|
59 | Under normal circumstances you don't need to call this function. |
|
|
60 | |
44 | $fileno = Linux::AIO::poll_fileno |
61 | $fileno = Linux::AIO::poll_fileno |
45 | Return the *request result pipe filehandle*. This filehandle must be |
62 | Return the *request result pipe filehandle*. This filehandle must be |
46 | polled for reading by some mechanism outside this module (e.g. Event |
63 | polled for reading by some mechanism outside this module (e.g. Event |
47 | or select, see below). If the pipe becomes readable you have to call |
64 | or select, see below). If the pipe becomes readable you have to call |
48 | "poll_cb" to check the results. |
65 | "poll_cb" to check the results. |
|
|
66 | |
|
|
67 | See "poll_cb" for an example. |
49 | |
68 | |
50 | Linux::AIO::poll_cb |
69 | Linux::AIO::poll_cb |
51 | Process all outstanding events on the result pipe. You have to call |
70 | Process all outstanding events on the result pipe. You have to call |
52 | this regularly. Returns the number of events processed. Returns |
71 | this regularly. Returns the number of events processed. Returns |
53 | immediately when no events are outstanding. |
72 | immediately when no events are outstanding. |
54 | |
73 | |
55 | You can use Event to multiplex, e.g.: |
74 | You can use Event to multiplex, e.g.: |
56 | |
75 | |
57 | Event->io (fd => Linux::AIO::poll_fileno, |
76 | Event->io (fd => Linux::AIO::poll_fileno, |
58 | poll => 'r', async => 1, |
77 | poll => 'r', async => 1, |
59 | cb => \&Linux::AIO::poll_cb ); |
78 | cb => \&Linux::AIO::poll_cb); |
60 | |
79 | |
61 | Linux::AIO::poll_wait |
80 | Linux::AIO::poll_wait |
62 | Wait till the result filehandle becomes ready for reading (simply |
81 | Wait till the result filehandle becomes ready for reading (simply |
63 | does a select on the filehandle. This is useful if you want to |
82 | does a select on the filehandle. This is useful if you want to |
64 | synchronously wait for some requests to finish). |
83 | synchronously wait for some requests to finish). |
65 | |
84 | |
|
|
85 | See "nreqs" for an example. |
|
|
86 | |
66 | Linux::AIO::nreqs |
87 | Linux::AIO::nreqs |
67 | Returns the number of requests currently outstanding. |
88 | Returns the number of requests currently outstanding. |
|
|
89 | |
|
|
90 | Example: wait till there are no outstanding requests anymore: |
|
|
91 | |
|
|
92 | Linux::AIO::poll_wait while Linux::AIO::nreqs; |
68 | |
93 | |
69 | aio_open $pathname, $flags, $mode, $callback |
94 | aio_open $pathname, $flags, $mode, $callback |
70 | Asynchronously open or create a file and call the callback with the |
95 | Asynchronously open or create a file and call the callback with the |
71 | filedescriptor (NOT a perl filehandle, sorry for that, but watch |
96 | filedescriptor (NOT a perl filehandle, sorry for that, but watch |
72 | out, this might change in the future). |
97 | out, this might change in the future). |
|
|
98 | |
|
|
99 | The $mode argument is a bitmask. See the "Fcntl" module for a list. |
|
|
100 | They are the same as used in "sysopen". |
|
|
101 | |
|
|
102 | Example: |
|
|
103 | |
|
|
104 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
|
|
105 | if ($_[0] >= 0) { |
|
|
106 | open my $fh, "<&$_[0]"; # create a copy for perl |
|
|
107 | aio_close $_[0], sub { }; # close the aio handle |
|
|
108 | print "open successful, fh is $fh\n"; |
|
|
109 | ... |
|
|
110 | } else { |
|
|
111 | die "open failed: $!\n"; |
|
|
112 | } |
|
|
113 | }; |
73 | |
114 | |
74 | aio_close $fh, $callback |
115 | aio_close $fh, $callback |
75 | Asynchronously close a file and call the callback with the result |
116 | Asynchronously close a file and call the callback with the result |
76 | code. |
117 | code. |
77 | |
118 | |
78 | aio_read $fh,$offset,$length, $data,$dataoffset,$callback |
119 | aio_read $fh,$offset,$length, $data,$dataoffset,$callback |
79 | aio_write $fh,$offset,$length, $data,$dataoffset,$callback |
120 | aio_write $fh,$offset,$length, $data,$dataoffset,$callback |
80 | Reads or writes "length" bytes from the specified "fh" and "offset" |
121 | Reads or writes "length" bytes from the specified "fh" and "offset" |
81 | into the scalar given by "data" and offset "dataoffset" and calls |
122 | into the scalar given by "data" and offset "dataoffset" and calls |
82 | the callback without the actual number of bytes read (or "undef" on |
123 | the callback without the actual number of bytes read (or -1 on |
83 | error). |
124 | error, just like the syscall). |
|
|
125 | |
|
|
126 | Example: Read 15 bytes at offset 7 into scalar $buffer, strating at |
|
|
127 | offset 0 within the scalar: |
|
|
128 | |
|
|
129 | aio_read $fh, 7, 15, $buffer, 0, sub { |
|
|
130 | $_[0] >= 0 or die "read error: $!"; |
|
|
131 | print "read <$buffer>\n"; |
|
|
132 | }; |
|
|
133 | |
|
|
134 | aio_readahead $fh,$offset,$length, $callback |
|
|
135 | Asynchronously reads the specified byte range into the page cache, |
|
|
136 | using the "readahead" syscall. |
|
|
137 | |
|
|
138 | readahead() populates the page cache with data from a file so that |
|
|
139 | subsequent reads from that file will not block on disk I/O. The |
|
|
140 | $offset argument specifies the starting point from which data is to |
|
|
141 | be read and $length specifies the number of bytes to be read. I/O is |
|
|
142 | performed in whole pages, so that offset is effectively rounded down |
|
|
143 | to a page boundary and bytes are read up to the next page boundary |
|
|
144 | greater than or equal to (off-set+length). aio_readahead() does not |
|
|
145 | read beyond the end of the file. The current file offset of the file |
|
|
146 | is left unchanged. |
84 | |
147 | |
85 | aio_stat $fh_or_path, $callback |
148 | aio_stat $fh_or_path, $callback |
86 | aio_lstat $fh, $callback |
149 | aio_lstat $fh, $callback |
87 | Works like perl's "stat" or "lstat" in void context. The callback |
150 | Works like perl's "stat" or "lstat" in void context. The callback |
88 | will be called after the stat and the results will be available |
151 | will be called after the stat and the results will be available |
… | |
… | |
91 | Currently, the stats are always 64-bit-stats, i.e. instead of |
154 | Currently, the stats are always 64-bit-stats, i.e. instead of |
92 | returning an error when stat'ing a large file, the results will be |
155 | returning an error when stat'ing a large file, the results will be |
93 | silently truncated unless perl itself is compiled with large file |
156 | silently truncated unless perl itself is compiled with large file |
94 | support. |
157 | support. |
95 | |
158 | |
|
|
159 | Example: Print the length of /etc/passwd: |
|
|
160 | |
|
|
161 | aio_stat "/etc/passwd", sub { |
|
|
162 | $_[0] and die "stat failed: $!"; |
|
|
163 | print "size is ", -s _, "\n"; |
|
|
164 | }; |
|
|
165 | |
96 | aio_unlink $pathname, $callback |
166 | aio_unlink $pathname, $callback |
97 | Asynchronously unlink a file. |
167 | Asynchronously unlink (delete) a file and call the callback with the |
|
|
168 | result code. |
|
|
169 | |
|
|
170 | aio_fsync $fh, $callback |
|
|
171 | Asynchronously call fsync on the given filehandle and call the |
|
|
172 | callback with the fsync result code. |
|
|
173 | |
|
|
174 | aio_fdatasync $fh, $callback |
|
|
175 | Asynchronously call fdatasync on the given filehandle and call the |
|
|
176 | callback with the fdatasync result code. |
98 | |
177 | |
99 | BUGS |
178 | BUGS |
100 | This module has been extensively tested in a large and very busy |
179 | This module has been extensively tested in a large and very busy |
101 | webserver for many years now. |
180 | webserver for many years now. |
102 | |
181 | |