[ViewVC] Diff of: cvs/IO-AIO/AIO.pm

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.153 by root, Sat Jun 13 13:33:00 2009 UTC vs.
Revision 1.171 by root, Sat Jan 2 14:24:32 2010 UTC

  # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
  use AnyEvent::AIO;
  # EV integration
- my $w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
+ my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
  # Event integration
  Event->io (fd => IO::AIO::poll_fileno,
             poll => 'r',
             cb => \&IO::AIO::poll_cb);
                              \&IO::AIO::poll_cb);
 =head1 DESCRIPTION
 This module implements asynchronous I/O using whatever means your
-operating system supports.
+operating system supports. It is implemented as an interface to C<libeio>
+(L<http://software.schmorp.de/pkg/libeio.html>).
 Asynchronous means that operations that can normally block your program
 (e.g. reading from disk) will be done asynchronously: the operation
 will still block, but you can do something else in the meantime. This
 is extremely useful for programs that need to stay interactive even
 on a RAID volume or over NFS when you do a number of stat operations
 concurrently.
 While most of this works on all types of file descriptors (for
 example sockets), using these functions on file descriptors that
-support nonblocking operation (again, sockets, pipes etc.) is very
+support nonblocking operation (again, sockets, pipes etc.) is
-inefficient. Use an event loop for that (such as the L<Event|Event>
+very inefficient. Use an event loop for that (such as the L<EV>
 module): IO::AIO will naturally fit into such an event loop itself.
 In this version, a number of threads are started that execute your
 requests and signal their completion. You don't need thread support
 in perl, and the threads created by this module will not be visible
 yourself, always call C<poll_cb> from within the same thread, or never
 call C<poll_cb> (or other C<aio_> functions) recursively.
 =head2 EXAMPLE
-This is a simple example that uses the Event module and loads
+This is a simple example that uses the EV module and loads
 F</etc/passwd> asynchronously:
    use Fcntl;
-   use Event;
+   use EV;
    use IO::AIO;
-   # register the IO::AIO callback with Event
+   # register the IO::AIO callback with EV
-   Event->io (fd => IO::AIO::poll_fileno,
+   my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
-              poll => 'r',
-              cb => \&IO::AIO::poll_cb);
    # queue the request to open /etc/passwd
    aio_open "/etc/passwd", O_RDONLY, 0, sub {
       my $fh = shift
          or die "error while opening: $!";
          # file contents now in $contents
          print $contents;
          # exit event loop and program
-         Event::unloop;
+         EV::unloop;
       };
    };
    # possibly queue up other requests, or open GUI windows,
    # check for sockets etc. etc.
    # process events as long as there are some:
-   Event::loop;
+   EV::loop;
 =head1 REQUEST ANATOMY AND LIFETIME
 Every C<aio_*> function creates a request. which is a C data structure not
 directly visible to Perl.
 package IO::AIO;
 use Carp ();
-no warnings;
+use common::sense;
-use strict 'vars';
 use base 'Exporter';
 BEGIN {
-   our $VERSION = '3.22';
+   our $VERSION = '3.4';
    our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close
                      aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
                      aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
                      aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead
                      aio_rename aio_link aio_move aio_copy aio_group
                      aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
-                     aio_chmod aio_utime aio_truncate);
+                     aio_chmod aio_utime aio_truncate
+                     aio_msync aio_mtouch);
    our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
    our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
                        min_parallel max_parallel max_idle
                        nreqs nready npending nthreads
-                       max_poll_time max_poll_reqs);
+                       max_poll_time max_poll_reqs
+                       sendfile fadvise);
    push @AIO_REQ, qw(aio_busy); # not exported
    @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
 This call tries to make use of a native C<sendfile> syscall to provide
 zero-copy operation. For this to work, C<$out_fh> should refer to a
 socket, and C<$in_fh> should refer to mmap'able file.
-If the native sendfile call fails or is not implemented, it will be
+If a native sendfile cannot be found or it fails with C<ENOSYS>,
+C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,
-emulated, so you can call C<aio_sendfile> on any type of filehandle
+it will be emulated, so you can call C<aio_sendfile> on any type of
-regardless of the limitations of the operating system.
+filehandle regardless of the limitations of the operating system.
 Please note, however, that C<aio_sendfile> can read more bytes from
 C<$in_fh> than are written, and there is no way to find out how many
 bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
 provides the number of bytes written to C<$out_fh>. Only if the result
 C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
 know, you have to run stat yourself. Also, for speed reasons, the C<$type>
 scalars are read-only: you can not modify them.
 C<$inode> is the inode number (which might not be exact on systems with 64
-bit inode numbers and 32 bit perls). On systems that do not deliver the
+bit inode numbers and 32 bit perls). This field has unspecified content on
-inode information, this will always be zero.
+systems that do not deliver the inode information.
 =item IO::AIO::READDIR_DIRS_FIRST
 When this flag is set, then the names will be returned in an order where
 likely directories come first. This is useful when you need to quickly
 =item aio_copy $srcpath, $dstpath, $callback->($status)
 Try to copy the I<file> (directories not supported as either source or
 destination) from C<$srcpath> to C<$dstpath> and call the callback with
-the C<0> (error) or C<-1> ok.
+a status of C<0> (ok) or C<-1> (error, see C<$!>).
 This is a composite request that creates the destination file with
 mode 0200 and copies the contents of the source file into it using
 C<aio_sendfile>, followed by restoring atime, mtime, access mode and
 uid/gid, in that order.
    my $grp = aio_group $cb;
    aioreq_pri $pri;
    add $grp aio_open $src, O_RDONLY, 0, sub {
       if (my $src_fh = $_[0]) {
-         my @stat = stat $src_fh; # hmm, might bock over nfs?
+         my @stat = stat $src_fh; # hmm, might block over nfs?
          aioreq_pri $pri;
          add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
             if (my $dst_fh = $_[0]) {
                aioreq_pri $pri;
 =item aio_move $srcpath, $dstpath, $callback->($status)
 Try to move the I<file> (directories not supported as either source or
 destination) from C<$srcpath> to C<$dstpath> and call the callback with
-the C<0> (error) or C<-1> ok.
+a status of C<0> (ok) or C<-1> (error, see C<$!>).
 This is a composite request that tries to rename(2) the file first; if
 rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
 that is successful, unlinks the C<$srcpath>.
 (E.g. rename). This might not work on all operating systems or have any
 specific effect, but usually it makes sure that directory changes get
 written to disc. It works for anything that can be opened for read-only,
 not just directories.
+Future versions of this function might fall back to other methods when
+C<fsync> on the directory fails (such as calling C<sync>).
 Passes C<0> when everything went ok, and C<-1> on error.
 =cut
 sub aio_pathsync($;$) {
    };
    $grp
 }
+=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
+This is a rather advanced IO::AIO call, which only works on mmap(2)ed
+scalars (see the L<Sys::Mmap> or L<Mmap> modules for details on this, note
+that the scalar must only be modified in-place while an aio operation is
+pending on it).
+It calls the C<msync> function of your OS, if available, with the memory
+area starting at C<$offset> in the string and ending C<$length> bytes
+later. If C<$length> is negative, counts from the end, and if C<$length>
+is C<undef>, then it goes till the end of the string. The flags can be
+a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
+C<IO::AIO::MS_SYNC>.
+=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
+This is a rather advanced IO::AIO call, which works best on mmap(2)ed
+scalars.
+It touches (reads or writes) all memory pages in the specified
+range inside the scalar.  All caveats and parameters are the same
+as for C<aio_msync>, above, except for flags, which must be either
+C<0> (which reads all pages and ensures they are instantiated) or
+C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
+writing an octet from it, which dirties the page).
 =item aio_group $callback->(...)
 This is a very special aio request: Instead of doing something, it is a
 container for other aio requests, which is useful if you want to bundle
 many requests into a single, composite, request with a definite callback
 =item $grp->cancel_subs
 Cancel all subrequests and clears any feeder, but not the group request
 itself. Useful when you queued a lot of events but got a result early.
+The group request will finish normally (you cannot add requests to the
+group).
 =item $grp->result (...)
 Set the result value(s) that will be passed to the group callback when all
 subrequests have finished and set the groups errno to the current value
 of errno (just like calling C<errno> without an error number). By default,
 =over 4
 =item $fileno = IO::AIO::poll_fileno
 Return the I<request result pipe file descriptor>. This filehandle must be
-polled for reading by some mechanism outside this module (e.g. Event or
+polled for reading by some mechanism outside this module (e.g. EV, Glib,
-select, see below or the SYNOPSIS). If the pipe becomes readable you have
+select and so on, see below or the SYNOPSIS). If the pipe becomes readable
-to call C<poll_cb> to check the results.
+you have to call C<poll_cb> to check the results.
 See C<poll_cb> for an example.
 =item IO::AIO::poll_cb
 If not all requests were processed for whatever reason, the filehandle
 will still be ready when C<poll_cb> returns, so normally you don't have to
 do anything special to have it called later.
 Example: Install an Event watcher that automatically calls
-IO::AIO::poll_cb with high priority:
+IO::AIO::poll_cb with high priority (more examples can be found in the
+SYNOPSIS section, at the top of this document):
    Event->io (fd => IO::AIO::poll_fileno,
               poll => 'r', async => 1,
               cb => \&IO::AIO::poll_cb);
 =item IO::AIO::npending
 Returns the number of requests currently in the pending state (executed,
 but not yet processed by poll_cb).
+=back
+=head3 MISCELLANEOUS FUNCTIONS
+IO::AIO implements some functions that might be useful, but are not
+asynchronous.
+=over 4
+=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
+Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
+but is blocking (this makes most sense if you know the input data is
+likely cached already and the output filehandle is set to non-blocking
+operations).
+Returns the number of bytes copied, or C<-1> on error.
+=item IO::AIO::fadvise $fh, $offset, $len, $advice
+Simply calls the C<posix_fadvise> function (see it's
+manpage for details). The following advice constants are
+avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
+C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
+C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
+On systems that do not implement C<posix_fadvise>, this function returns
+ENOSYS, otherwise the return value of C<posix_fadvise>.
 =back
 =cut

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing IO-AIO/AIO.pm (file contents): Revision 1.153 by root, Sat Jun 13 13:33:00 2009 UTC vs. Revision 1.171 by root, Sat Jan 2 14:24:32 2010 UTC

Diff Legend

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.153 by root, Sat Jun 13 13:33:00 2009 UTC vs.
Revision 1.171 by root, Sat Jan 2 14:24:32 2010 UTC