--- IO-AIO/AIO.pm 2005/07/13 00:13:09 1.21 +++ IO-AIO/AIO.pm 2006/06/24 16:27:02 1.50 @@ -17,6 +17,10 @@ $_[0] > 0 or die "read error: $!"; }; + # AnyEvent + open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!"; + my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb }); + # Event Event->io (fd => IO::AIO::poll_fileno, poll => 'r', @@ -24,7 +28,7 @@ # Glib/Gtk2 add_watch Glib::IO IO::AIO::poll_fileno, - in => sub { IO::AIO::poll_cb, 1 }; + in => sub { IO::AIO::poll_cb; 1 }; # Tk Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", @@ -50,22 +54,28 @@ remaining functionality would have to be implemented using threads anyway. Although the module will work with in the presence of other threads, it is -currently not reentrant, so use appropriate locking yourself. +currently not reentrant, so use appropriate locking yourself, always call +C from within the same thread, or never call C (or other +C functions) recursively. =cut package IO::AIO; +no warnings; + use base 'Exporter'; use Fcntl (); BEGIN { - $VERSION = 0.9; + $VERSION = '1.8'; - @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink - aio_fsync aio_fdatasync aio_readahead); - @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs); + @EXPORT = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat + aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink + aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move); + @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel + max_outstanding nreqs); require XSLoader; XSLoader::load IO::AIO, $VERSION; @@ -83,16 +93,25 @@ perl, which usually delivers "false") as it's sole argument when the given syscall has been executed asynchronously. -All functions that expect a filehandle will also accept a file descriptor. +All functions expecting a filehandle keep a copy of the filehandle +internally until the request has finished. -The filenames you pass to these routines I be absolute. The reason -for this is that at the time the request is being executed, the current -working directory could have changed. Alternatively, you can make sure -that you never change the current working directory. +The pathnames you pass to these routines I be absolute and +encoded in byte form. The reason for the former is that at the time the +request is being executed, the current working directory could have +changed. Alternatively, you can make sure that you never change the +current working directory. + +To encode pathnames to byte form, either make sure you either: a) +always pass in filenames you got from outside (command line, readdir +etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode +your pathnames to the locale (or other) encoding in effect in the user +environment, d) use Glib::filename_from_unicode on unicode filenames or e) +use something else. =over 4 -=item aio_open $pathname, $flags, $mode, $callback +=item aio_open $pathname, $flags, $mode, $callback->($fh) Asynchronously open or create a file and call the callback with a newly created filehandle for the file. @@ -119,7 +138,7 @@ } }; -=item aio_close $fh, $callback +=item aio_close $fh, $callback->($status) Asynchronously close a file and call the callback with the result code. I although accepted, you should not pass in a perl @@ -130,15 +149,19 @@ This is supposed to be a bug in the API, so that might change. It's therefore best to avoid this function. -=item aio_read $fh,$offset,$length, $data,$dataoffset,$callback +=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) -=item aio_write $fh,$offset,$length, $data,$dataoffset,$callback +=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) Reads or writes C bytes from the specified C and C into the scalar given by C and offset C and calls the callback without the actual number of bytes read (or -1 on error, just like the syscall). +The C<$data> scalar I be modified in any way while the request +is outstanding. Modifying it can result in segfaults or WW3 (if the +necessary/optional hardware is installed). + Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at offset C<0> within the scalar: @@ -147,11 +170,95 @@ print "read $_[0] bytes: <$buffer>\n"; }; -=item aio_readahead $fh,$offset,$length, $callback +=item aio_move $srcpath, $dstpath, $callback->($status) + +[EXPERIMENTAL] + +Try to move the I (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. + +This is a composite request that tries to rename(2) the file first. If +rename files with C, it creates the destination file with mode 0200 +and copies the contents of the source file into it using C, +followed by restoring atime, mtime, access mode and uid/gid, in that +order, and unlinking the C<$srcpath>. + +If an error occurs, the partial destination file will be unlinked, if +possible, except when setting atime, mtime, access mode and uid/gid, where +errors are being ignored. + +=cut + +sub aio_move($$$) { + my ($src, $dst, $cb) = @_; + + aio_rename $src, $dst, sub { + if ($_[0] && $! == Errno::EXDEV) { + aio_open $src, O_RDONLY, 0, sub { + if (my $src_fh = $_[0]) { + my @stat = stat $src_fh; + + aio_open $dst, O_WRONLY, 0200, sub { + if (my $dst_fh = $_[0]) { + aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { + close $src_fh; + + if ($_[0] == $stat[7]) { + utime $stat[8], $stat[9], $dst; + chmod $stat[2] & 07777, $dst_fh; + chown $stat[4], $stat[5], $dst_fh; + close $dst_fh; + + aio_unlink $src, sub { + $cb->($_[0]); + }; + } else { + my $errno = $!; + aio_unlink $dst, sub { + $! = $errno; + $cb->(-1); + }; + } + }; + } else { + $cb->(-1); + } + }, + + } else { + $cb->(-1); + } + }; + } else { + $cb->($_[0]); + } + }; +} -Asynchronously reads the specified byte range into the page cache, using -the C syscall. If that syscall doesn't exist (likely if your OS -isn't Linux) the status will be C<-1> and C<$!> is set to C. +=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) + +Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts +reading at byte offset C<$in_offset>, and starts writing at the current +file offset of C<$out_fh>. Because of that, it is not safe to issue more +than one C per C<$out_fh>, as they will interfere with each +other. + +This call tries to make use of a native C 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 +emulated, so you can call C on any type of filehandle +regardless of the limitations of the operating system. + +Please note, however, that C 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 alone, as C only +provides the number of bytes written to C<$out_fh>. Only if the result +value equals C<$length> one can assume that C<$length> bytes have been +read. + +=item aio_readahead $fh,$offset,$length, $callback->($retval) C populates the page cache with data from a file so that subsequent reads from that file will not block on disk I/O. The C<$offset> @@ -162,9 +269,12 @@ (off-set+length). C does not read beyond the end of the file. The current file offset of the file is left unchanged. -=item aio_stat $fh_or_path, $callback +If that syscall doesn't exist (likely if your OS isn't Linux) it will be +emulated by simply reading the data, which would have a similar effect. -=item aio_lstat $fh, $callback +=item aio_stat $fh_or_path, $callback->($status) + +=item aio_lstat $fh, $callback->($status) Works like perl's C or C in void context. The callback will be called after the stat and the results will be available using C @@ -184,21 +294,189 @@ print "size is ", -s _, "\n"; }; -=item aio_unlink $pathname, $callback +=item aio_unlink $pathname, $callback->($status) Asynchronously unlink (delete) a file and call the callback with the result code. -=item aio_fsync $fh, $callback +=item aio_link $srcpath, $dstpath, $callback->($status) + +Asynchronously create a new link to the existing object at C<$srcpath> at +the path C<$dstpath> and call the callback with the result code. + +=item aio_symlink $srcpath, $dstpath, $callback->($status) + +Asynchronously create a new symbolic link to the existing object at C<$srcpath> at +the path C<$dstpath> and call the callback with the result code. + +=item aio_rename $srcpath, $dstpath, $callback->($status) + +Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as +rename(2) and call the callback with the result code. + +=item aio_rmdir $pathname, $callback->($status) + +Asynchronously rmdir (delete) a directory and call the callback with the +result code. + +=item aio_readdir $pathname, $callback->($entries) + +Unlike the POSIX call of the same name, C reads an entire +directory (i.e. opendir + readdir + closedir). The entries will not be +sorted, and will B include the C<.> and C<..> entries. + +The callback a single argument which is either C or an array-ref +with the filenames. + +=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) + +Scans a directory (similar to C) and tries to separate the +entries of directory C<$path> into two sets of names, ones you can recurse +into (directories), and ones you cannot recurse into (everything else). + +C is a composite request that consists of many +aio-primitives. C<$maxreq> specifies the maximum number of outstanding +aio requests that this function generates. If it is C<< <= 0 >>, then a +suitable default will be chosen (currently 8). + +On error, the callback is called without arguments, otherwise it receives +two array-refs with path-relative entry names. + +Example: + + aio_scandir $dir, 0, sub { + my ($dirs, $nondirs) = @_; + print "real directories: @$dirs\n"; + print "everything else: @$nondirs\n"; + }; + +Implementation notes. + +The C cannot be avoided, but C'ing every entry can. + +After reading the directory, the modification time, size etc. of the +directory before and after the readdir is checked, and if they match, the +link count will be used to decide how many entries are directories (if +>= 2). Otherwise, no knowledge of the number of subdirectories will be +assumed. + +Then entires will be sorted into likely directories (everything without a +non-initial dot) and likely non-directories (everything else). Then every +entry + C will be C'ed, likely directories first. This is often +faster because filesystems might detect the type of the entry without +reading the inode data (e.g. ext2fs filetype feature). If that succeeds, +it assumes that the entry is a directory or a symlink to directory (which +will be checked seperately). + +If the known number of directories has been reached, the rest of the +entries is assumed to be non-directories. + +=cut + +sub aio_scandir($$$) { + my ($path, $maxreq, $cb) = @_; + + $maxreq = 8 if $maxreq <= 0; + + # stat once + aio_stat $path, sub { + return $cb->() if $_[0]; + my $hash1 = join ":", (stat _)[0,1,3,7,9]; + + # read the directory entries + aio_readdir $path, sub { + my $entries = shift + or return $cb->(); + + # stat the dir another time + aio_stat $path, sub { + my $hash2 = join ":", (stat _)[0,1,3,7,9]; + + my $ndirs; + + # take the slow route if anything looks fishy + if ($hash1 ne $hash2) { + $ndirs = -1; + } else { + # if nlink == 2, we are finished + # on non-posix-fs's, we rely on nlink < 2 + $ndirs = (stat _)[3] - 2 + or return $cb->([], $entries); + } + + # sort into likely dirs and likely nondirs + # dirs == files without ".", short entries first + $entries = [map $_->[0], + sort { $b->[1] cmp $a->[1] } + map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], + @$entries]; + + my (@dirs, @nondirs); + + my ($statcb, $schedcb); + my $nreq = 0; + + $schedcb = sub { + if (@$entries) { + if ($nreq < $maxreq) { + my $ent = pop @$entries; + $nreq++; + aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) }; + } + } elsif (!$nreq) { + # finished + undef $statcb; + undef $schedcb; + $cb->(\@dirs, \@nondirs) if $cb; + undef $cb; + } + }; + $statcb = sub { + my ($status, $entry) = @_; + + if ($status < 0) { + $nreq--; + push @nondirs, $entry; + &$schedcb; + } else { + # need to check for real directory + aio_lstat "$path/$entry", sub { + $nreq--; + + if (-d _) { + push @dirs, $entry; + + if (!--$ndirs) { + push @nondirs, @$entries; + $entries = []; + } + } else { + push @nondirs, $entry; + } + + &$schedcb; + } + } + }; + + &$schedcb while @$entries && $nreq < $maxreq; + }; + }; + }; +} + +=item aio_fsync $fh, $callback->($status) Asynchronously call fsync on the given filehandle and call the callback with the fsync result code. -=item aio_fdatasync $fh, $callback +=item aio_fdatasync $fh, $callback->($status) Asynchronously call fdatasync on the given filehandle and call the -callback with the fdatasync result code. Might set C<$!> to C if -C is not available. +callback with the fdatasync result code. + +If this call isn't available because your OS lacks it or it couldn't be +detected, it will be emulated by calling C instead. =back @@ -266,24 +544,29 @@ =item IO::AIO::min_parallel $nthreads -Set the minimum number of AIO threads to C<$nthreads>. The default is -C<1>, which means a single asynchronous operation can be done at one time +Set the minimum number of AIO threads to C<$nthreads>. The current default +is C<4>, which means four asynchronous operations can be done at one time (the number of outstanding operations, however, is unlimited). +IO::AIO starts threads only on demand, when an AIO request is queued and +no free thread exists. + It is recommended to keep the number of threads low, as some Linux kernel versions will scale negatively with the number of threads (higher parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32 threads should be fine. -Under normal circumstances you don't need to call this function, as this -module automatically starts some threads (the exact number might change, -and is currently 4). +Under most circumstances you don't need to call this function, as the +module selects a default that is suitable for low to moderate load. =item IO::AIO::max_parallel $nthreads -Sets the maximum number of AIO threads to C<$nthreads>. If more than -the specified number of threads are currently running, kill them. This -function blocks until the limit is reached. +Sets the maximum number of AIO threads to C<$nthreads>. If more than the +specified number of threads are currently running, this function kills +them. This function blocks until the limit is reached. + +While C<$nthreads> are zero, aio requests get queued but not executed +until the number of threads has been increased again. This module automatically runs C at program end, to ensure that all threads are killed and that there are no outstanding requests. @@ -297,7 +580,7 @@ some requests have been handled. The default is very large, so normally there is no practical limit. If you -queue up many requests in a loop it it often improves speed if you set +queue up many requests in a loop it often improves speed if you set this to a relatively low number, such as C<100>. Under normal circumstances you don't need to call this function. @@ -310,12 +593,16 @@ sub _fd2fh { return undef if $_[0] < 0; - # try to be perl5.6-compatible - local *AIO_FH; - open AIO_FH, "+<&=$_[0]" + # try to generate nice filehandles + my $sym = "IO::AIO::fd#$_[0]"; + local *$sym; + + open *$sym, "+<&=$_[0]" # usually works under any unix + or open *$sym, "<&=$_[0]" # cygwin needs this + or open *$sym, ">&=$_[0]" # or this or return undef; - *AIO_FH + *$sym } min_parallel 4; @@ -326,6 +613,16 @@ 1; +=head2 FORK BEHAVIOUR + +Before the fork, IO::AIO enters a quiescent state where no requests +can be added in other threads and no results will be processed. After +the fork the parent simply leaves the quiescent state and continues +request/result processing, while the child clears the request/result +queue (so the requests started before the fork will only be handled in +the parent). Threats will be started on demand until the limit ste in the +parent process has been reached again. + =head1 SEE ALSO L, L.