[ViewVC] Annotation of: cvs/IO-AIO/Changes

Revision history for IO::AIO

TODO: better autoconf.pm that can return LIBS etc.
TODO: aio_cptree/mvtree
TODO: reduce condvar fairness: schedule hot-cache-threads first?
TODO: splice/tee/vmsplice? (http://kerneltrap.org/node/6505 http://lwn.net/Articles/178199/)
TODO: aio_fcntl, at least for file-locking
TODO: fallocate, if it wouldn't be so useless.

        - (libeio) replaced quicksort+insertion sort by a tuned radix
          sort + insertion sort, resulting in comparable runtime (usually
          faster) to the old version, but without any ill side effects on
          degenerated (for quicksort) data.
        - (libeio) correctly sort dirs by inodes if we have perfect type
          knowledge and DIRS_FIRST is used.
        - (libeio) internally the wrong DT_* constants were used, but no
          known system has differing EIO_DT_*/DT_* values, so not an issue.
        - removed a (harmless) assert that was left over on the code
          but should not have been.
        - added IO::AIO::fadvise and IO::AIO::sendfile.
        - use more correct types (change IO length from IV to VAL64,
          which makes a difference on systems without 64 bit perls).

3.23 Sat Jun 13 16:57:58 CEST 2009
        - fix off-by-one bug in aio_readdir that was introduced in the
          rushed 3.22 release.

3.22 Sat Jun 13 15:32:40 CEST 2009
        - speed up readdirx sort algorithm slightly.
        - bin/treescan was missing from distro tarball.

3.21 Fri Jun 12 18:45:53 CEST 2009
        - new options --dirs and --files for treescan.
        - install bin/treescan by default.
        - (libeio) aio_readdir can now be cancelled while executing.
        - fix a printf format string for 64 bit systems (could lead
          to problems on big endian 64 bit systems).
        - do not use qsort() but our own algorithm: glibc initialises
          the whole locale and I/O subsystem inside qsort, causing
          a stack overflow on 32 bit machines. The new sort uses much less
          stack and is more than twice as fast in typical situations.

3.2  Sun Jun  7 20:30:05 CEST 2009
        - (libeio) pwrite emulation was even more flawed than intended and did
          not restore the file offset.
        - add aio_readdirx, which can return inode and filetype and sort
          the names in various ways.
        - unfortunately, utime, chmod, chown on an open file that has just
          been written can easily block, which caused aio_copy to block the
          process. no more!
        - no longer rely on dst path in aio_copy when futime is available.

3.19 Tue Apr 21 22:05:21 CEST 2009
        - more perl 5.10 workarounds for aio_read and write.
        - aio_write no longer modifies the sv (if possible).
        - aio_read now works correctly with magic values.

3.18 Sun Apr 19 21:17:32 CEST 2009
        - better diagnostics when some aio_* functions get passed an illegal fh.
        - try to avoid crashes due to incompatible 5.10 API changes. grmbl.

3.17 Thu Nov 20 08:45:36 CET 2008
        - (libeio) added aio_sync_file_range (untested).
        - add aio_busy to @IO::AIO::AIO_REQ.

3.16 Wed Oct 22 18:28:01 CEST 2008
        - use SvREFCNT_inc instead of SvREFCNT_inc_NN in a non-speed critical
          part to improve portability to perl 5.8 (reported by szymon).

3.15 Mon Oct 13 00:39:55 CEST 2008
        - automatic removal of feeders was broken.
        - (libeio) use a more robust method to detect whether a feeder
          has added something to the group or not.

3.1  Thu Oct  2 13:34:40 CEST 2008
        - pre-deref the passed callback object, for increased speed
          and decreased memory usage.
        - call on_next_submit callback even for aio_group - impact unknown,
          but seems more correct.
        - $req->cb now returns the original callback.
        - (libeio) pass EIO_GROUP/aio_group requests through the queue without
          requiring a thread switch.
        - (libeio) status code of aio_futime and aio_utime was always passed 0.
        - do some other µ-optimisations.

3.07 Sat Aug  2 16:06:13 CEST 2008
        - do not include LIBS in autoconf tests.

3.06 Tue Jul 15 12:41:32 CEST 2008
        - move preadwritelock definition before it's first reference,
          to make it compile again on broken platforms (they still exist)
          or badly cofngiured perls (redhat...), reported by Rob Bloodgood.

3.05 Thu Jun 19 23:23:52 CEST 2008
        - work around perl overriding readdir etc. with thread-unsafe
          (sic!) versions.

3.04 Wed Jun 18 01:35:38 CEST 2008
        - (libeio) fix eio_mknod, which confused it's arguments.
        - (libeio) do not use readdir_r, as Ulrich Drepper pointed out that this
          is stupid.
        - (libeio) fix eio__readahead prototype, patch by Jost Krieger.
        - (libeio) fix a bug that could potentially cause IO::AIO
          not to get initialised properly.

3.03 Thu May 29 05:33:30 CEST 2008
        - (libeio) correctly call pthread_attr_destroy ().
        - (libeio) work around broken bsd headers once more.
        - reduce shared library size again by not including wrappers.
        - max_outstanding could cause poll to enter a busy-waiting loop.
        - document the new IO::AIO::poll_cb result value.

3.02 Mon May 12 02:32:02 CEST 2008
        - fix a memory leak on aio_readlink.
        - bring back working fchmod.
        - nop and busy now set result to 0.
        - set errno to ENOMEM when allocation fails.

3.01 Sun May 11 03:07:03 CEST 2008
        - (libeio) make it compile on systems without readahead or readdir_r.
        - (libeio) improve configure check for readahead availability.
        - do not try to link against -lrt.
        - use a separate configure script for IO::AIO (not the libeio one).

3.0  Sun May 11 00:57:14 CEST 2008
        - added bin/treescan to the distribution.
        - switched to using libeio.
        - LOTS OF INCOMPATIBLE CHANGES:
          - remove signal functionality, it is not worth the effort.
          - max_outstanding no longer returns the previous number of requests.
          - poll_cb no longer returns number of requests.

2.62 Sat Apr 26 13:59:33 CEST 2008
        - port to solaris perls configured for old posix
          (analysed by Jost Krieger).
        - keep a reference to the perl filehandle object in aio_close,
          so it doesn't get closed prematurely, leading to ugly races.

2.61 Wed Apr 16 18:45:02 CEST 2008
        - fix treescan output duplication and improve output ordering.
          also display files given on the commandline.
        - use a different algorithm for aio_close that is faster
          and probably has even lower chances of blocking.
        - do our own stack memory management for threads - linux
          allocates outrageous amounts of VM (not so bad unless you
          use mlockall...), which severely limits the number of threads
          on 32-bit arches: stack size is the larger of PTHREAD_STACK_MIN
          and 4096 * sizeof (long) (usually this is 16..64k).

2.6  Sun Mar 30 08:28:11 CEST 2008
        - added aio_sync.
        - added aio_pathsync.
        - fix prototypes of (void) functions.

2.51 Sat Oct  6 16:04:54 CEST 2007
        - perlio isn't generally threadsafe, so aio_close could not work reliably.
          aio_close now tries a safe hack that might not be that asynchronous
          (see the manpage for details).
        - discard callback return values as to not grow the stack endlessly
          when poll_cb handles many requests without returning.
        - minor code cleanups.

2.5  Thu Oct  4 14:49:08 CEST 2007
        - replaced _fd2fh with faster xs code.
        - aio_close will now try to do "the right thing" and thus might
          work sensibly for the very first time.

2.41 Mon Sep 24 21:28:21 CEST 2007
        - after fork, invest some work to make sure that the poll_fileno
          stays stable (by dup2'ing the new fd over the old one), to make
          it easier for programs/libs that don't control their forking
          behaviour and cannot recreate their watchers.

2.4  Sun Aug  5 18:44:22 CEST 2007
        - add aio_truncate, aio_chmod, aio_chown, aio_utime (linux
          successfully demonstrated that you can block on futimes...).
        - allow undef as fileoffset for aio_read/write and use read/write(2)
          internally (useful for sockets or O_APPEND handles).
        - allow undef for length in aio_write.
        - negative dataoffsets work as expected now in aio_read/aio_write.
        - use NV instead of UV for 32 bit perls and file offsets, as NVs
          have a larger range then.
        - shared code between BDB and IO::AIO.
        - aio_busy was completely broken. now fixed.
        - readahead emulation now returns something.
        - correctly set errno to ENOSYS on unimplemented functions
          (should never happen, though).
        - large changes to make it partially compile and run on win32,
          but win32 lacks too much functionality, and perl overrides way
          too many functions with crashing versions.

2.33 Tue Jan 23 23:55:41 CET 2007
        - fix install path (Andreas J. Koenig).

2.32 Mon Jan 22 16:56:23 CET 2007
        - added aio_rmtree.
        - wow, aio_mkdir was missing.
        - aio_load did return undef on error, not -1.
        - use prefixexp not prefix in autoconf.pm
          (suggested by ... rt.cpan.org unreachable).
        - avoid installing autoconf.pm.

2.31 Sat Jan  6 03:46:02 CET 2007
        - added aio_load.

2.3  Sat Dec 23 05:48:07 CET 2006
        - fix off-by-one bug in aio_read, causing memory corruption
          or crashes.

2.21  Fri Dec 22 05:03:38 CET 2006
        - minor doc updates.
        - minor cleanups.
        - IO::AIO::poll returns request count.
        - undocumented and unfinished async-signal-reporting.

2.2  Tue Oct 31 00:31:00 CET 2006
        - minor doc updates.
        - added aio_readlink.
        - properly zero-terminate aio_read buffer.
        - fix aio_read/write with nonzero dataoffset.
        - reduced size of aio request structure.
        - better diagnostics when pathnames etc. are not byte-encoded;
          do not leak request in that case, either.

2.1  Sun Oct 29 02:01:57 CET 2006
        - INCOMPATIBLE CHANGE: replace IO::AIO::poll_some by
          IO::AIO::max_poll_reqs and IO::AIO::max_poll_time.
        - fix a bug in aio_move where it would fail everytime
          it would have to copy files manually.
        - doc updates.
        - start threads only on (very low) demand.
        - end superfluous threads automatically after 10s idling.
        - add IO::AIO::max_idle to control this.
        - some tuning applied to random places.
        - add aio_mknod.

2.0  Thu Oct 26 18:27:58 CEST 2006
        - minor incompatibility: max_outstanding semantics have changed.
        - major rewrite, consider all functionality EXPERIMENTAL.
        - aio requests can be cancelled.
        - callbacks can be (re-)set later.
        - aio requests can choose between 9 priorities.
        - add aio_group: aio requests can be grouped
          into composite requests.
        - generator interface for groups.
        - add IO::AIO::poll_some.
        - major documentation improvements.
        - very minor bugfixes.
        - add aio_nop for dummy requests.
        - add aio_busy mainly for benchmarking and debugging.
        - use "fast" mutexes on linux.
        - use dynamic (and larger) buffers instead of
          putting them onto the stack.
        - optimise x86 and amd64 a bit.
        - better error checking when ENOMEM.
        - hopefully fix mem and dirp leaks on fork.
        - warn about broken perl malloc.
        - compiles on cygwin (but pread is broken on cygwin
          which is not detected by autoconf, so you have to
          edit autoconf/config.h yourself to enable emulation).

1.8  Sat Jun 24 22:20:44 CEST 2006
        - add and/or document aio_rename, aio_link, aio_symlink and aio_move.

1.73 Wed Mar  1 22:49:32 CET 2006
        - codename "jost"
        - AIX/Solaris(?) aren't being helpful again, hardcode a value
          for NAME_MAX and drive with your eyes closed (reported by
          wcooley@nakedape.cc).

1.72 Thu Feb  2 00:40:44 CET 2006
        - another minor bug in aio_scandir, again, the callback was called
          twice when the directory can't be stat'ed.

1.71 Mon Dec 26 20:20:03 CET 2005
        - grr, another minor bug in aio_scandir, this time resulting
          in a runtime error.

1.7  Mon Dec 26 19:29:48 CET 2005
        - aio_scandir errornously called callback twice in some cases.
        - added AnyEvent example.

1.61 Wed Sep  7 19:40:42 CEST 2005
        - no longer include $Config{libs}, as distros include too much
          garbage in there that is not installed on typical systems
          (for example, debian links perl against -lgdbm and many more
          libraries despite perl not needing it, slowing down startup and
          wasting memory).

1.6  Tue Aug 30 17:44:44 CEST 2005
        - added aio_readdir, aio_scandir.
        - added aio_sendfile, including sendfile emulation when sendfile
          isn't available. Linux, FreeBSD and HP-UX might work (sendfilev
          support is unavailable on my solaris 8 machine, but preliminary
          code is there. What's lacking is configury stuff and testing...).

1.5  Sat Aug 20 02:32:19 CEST 2005
        - create the aio threads on demand only (good after forking).
        - somebody nagged about C89 compatibility, so this release should
          be C89 compatible, but no guarantees for future ones.
        - abort when the configure script fails.

1.4  Wed Aug 17 08:07:27 CEST 2005
        - forgot to recreate the pipe after forking, this could cause
          deadlocks.

1.3  Wed Aug 17 07:25:54 CEST 2005
        - properly propagate exceptions from callbacks, instead of silently
          eating them.
        - use a different fork algorithm that avoids recursive callback
          invocations and reduces fork latency in busy processes.
        - fix a bug where the buffer scalar in aio_read got assigned the wrong
          length after reading.
        - fix a bug where the child would process some outstanding requests
          from the parent.
        - make a copy of the callback scalar, to avoid some very uncommon
          (but valid) usages where the callback scalar changes.
        - the callback was never freed in aio_read/aio_write.
        - aio_read/aio_write will now set the readonly flag on the data
          scalar for better error reporting.

1.2  Wed Aug 17 01:22:58 CEST 2005
        - verified on cygwin, linux/amd64+ia32+alpha, solaris.
        - use SvPVbyte for filenames now. You *need* to encode your strings to
          the external filename encoding first.
        - fix the bug where filehandles could leak (again).
        - clarify freebsd situation: make it work and tell me how, or go away
          with your underdocumented, broken and outdated OS.
        - fork'ing should now be officially supported (where linux and
          posix contradict each other, I followed posix).
        - only call read() once per poll, not twice (speedup).
        - new functions: aio_rmdir, aio_symlink.
        - force callback arguments to be undef or a reference, for better
          error catching.

1.1  Sun Aug  7 05:27:23 CEST 2005
        - added configure script to detect availability of some calls.
          (imperfect, as we cannot detect things like -lrt due to missing
          feedback yet).
        - emulate fdatasync via fsync, pread/pwrite via unsafe read/write
          and readahead via manual reading on platforms lacking those.
        - ported t/03_errors.t+framework by Brad Fitzpatrick
          from Linux::AIO.
        - removed XOPEN_SOURCE because stupid solaris 9 doesn't
          compile with it enabled. Probably breaks others. Oh well.
        - try to be more careful with errno on non-threaded perls.
        - cygwins perl insisted on a matching open mode when morphing
          the fd to an fh.
        - convert sv's to "byte" encoding in aio_read/aio_write. Might
          do that for pathnames, too, in the future, so make sure you
          properly encode your pathnames.

1.0  Fri Jul 22 10:43:30 CEST 2005
        - aio_open did not reliably deliver (open) filehandles.
        - all aio_*-functions keep a reference to the filehandle so
          it doesn't go away while the aio requests is working on it.
        - disable warnings in AIO.pm.

0.9  Wed Jul 20 23:55:04 CEST 2005
        - allow recursive calls to poll_cb, use less locking calls, too.
        - fix the Gtk2-example in the SYNOPSIS.
        - use pread/pwrite not pread64/pwrite64. this was simply a leftover
          from Linux::AIO.
          (found by compiling on cygwin. Unfortunately, cygwin declares but
          does not implement pread/pwrite).
        - only include <sys/syscall.h> on linux.

0.5  Tue Jul 12 13:03:09 CEST 2005
        - removed #include <endian.h>, it's not portable, and we don't
          need it anyway.
        - link against -lrt, as it might contain goodies such as fdatasync,
          and often aio_read, which we do not use yet, but it shouldn't hurt.

0.4  Mon Jul 11 05:28:25 CEST 2005
        - added IO::AIO::flush, IO::AIO::poll.
        - make callback argument optional for all calls.

0.3  Mon Jul 11 01:42:37 CEST 2005
        - restructured manpage.
        - added SYNOPSIS with examples for Event, Glib, Tk.
        - remove explicit context support so I don't have to maintain
          it for threaded perls (i.e. it should work now :).

0.2  Sun Jul 10 22:57:12 CEST 2005
        - return immediately from poll_wait if nreqs==0.
        - get rid of the request pipe and use faster thread-thread
          communications for most requests and responses.

0.1
        - cloned from Linux::AIO, which is very similar.

Revision:	1.196
Committed:	Wed Jun 17 01:14:48 2009 UTC (14 years, 11 months ago) by root
Branch:	MAIN
Changes since 1.195:	+4 -0 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.31	Revision history for IO::AIO
2	root	1.30
3	root	1.59	TODO: better autoconf.pm that can return LIBS etc.
4	root	1.114	TODO: aio_cptree/mvtree
5	root	1.106	TODO: reduce condvar fairness: schedule hot-cache-threads first?
6	root	1.176	TODO: splice/tee/vmsplice? (http://kerneltrap.org/node/6505 http://lwn.net/Articles/178199/)
7	root	1.136	TODO: aio_fcntl, at least for file-locking
8	root	1.196	TODO: fallocate, if it wouldn't be so useless.
9	root	1.100
10	root	1.195	- (libeio) replaced quicksort+insertion sort by a tuned radix
11			sort + insertion sort, resulting in comparable runtime (usually
12			faster) to the old version, but without any ill side effects on
13			degenerated (for quicksort) data.
14			- (libeio) correctly sort dirs by inodes if we have perfect type
15	root	1.194	knowledge and DIRS_FIRST is used.
16	root	1.195	- (libeio) internally the wrong DT_* constants were used, but no
17			known system has differing EIO_DT_/DT_ values, so not an issue.
18			- removed a (harmless) assert that was left over on the code
19			but should not have been.
20	root	1.196	- added IO::AIO::fadvise and IO::AIO::sendfile.
21			- use more correct types (change IO length from IV to VAL64,
22			which makes a difference on systems without 64 bit perls).
23	root	1.194
24	root	1.193	3.23 Sat Jun 13 16:57:58 CEST 2009
25			- fix off-by-one bug in aio_readdir that was introduced in the
26			rushed 3.22 release.
27
28	root	1.192	3.22 Sat Jun 13 15:32:40 CEST 2009
29	root	1.191	- speed up readdirx sort algorithm slightly.
30	root	1.192	- bin/treescan was missing from distro tarball.
31	root	1.191
32	root	1.190	3.21 Fri Jun 12 18:45:53 CEST 2009
33	root	1.187	- new options --dirs and --files for treescan.
34	root	1.188	- install bin/treescan by default.
35	root	1.189	- (libeio) aio_readdir can now be cancelled while executing.
36	root	1.190	- fix a printf format string for 64 bit systems (could lead
37			to problems on big endian 64 bit systems).
38			- do not use qsort() but our own algorithm: glibc initialises
39			the whole locale and I/O subsystem inside qsort, causing
40			a stack overflow on 32 bit machines. The new sort uses much less
41			stack and is more than twice as fast in typical situations.
42	root	1.187
43	root	1.186	3.2 Sun Jun 7 20:30:05 CEST 2009
44	root	1.182	- (libeio) pwrite emulation was even more flawed than intended and did
45			not restore the file offset.
46	root	1.183	- add aio_readdirx, which can return inode and filetype and sort
47			the names in various ways.
48	root	1.182	- unfortunately, utime, chmod, chown on an open file that has just
49			been written can easily block, which caused aio_copy to block the
50			process. no more!
51			- no longer rely on dst path in aio_copy when futime is available.
52
53	root	1.181	3.19 Tue Apr 21 22:05:21 CEST 2009
54			- more perl 5.10 workarounds for aio_read and write.
55			- aio_write no longer modifies the sv (if possible).
56			- aio_read now works correctly with magic values.
57
58	root	1.180	3.18 Sun Apr 19 21:17:32 CEST 2009
59	root	1.179	- better diagnostics when some aio_* functions get passed an illegal fh.
60	root	1.180	- try to avoid crashes due to incompatible 5.10 API changes. grmbl.
61	root	1.178
62	root	1.177	3.17 Thu Nov 20 08:45:36 CET 2008
63	root	1.176	- (libeio) added aio_sync_file_range (untested).
64	root	1.177	- add aio_busy to @IO::AIO::AIO_REQ.
65	root	1.175
66	root	1.174	3.16 Wed Oct 22 18:28:01 CEST 2008
67	root	1.173	- use SvREFCNT_inc instead of SvREFCNT_inc_NN in a non-speed critical
68			part to improve portability to perl 5.8 (reported by szymon).
69
70	root	1.172	3.15 Mon Oct 13 00:39:55 CEST 2008
71	root	1.171	- automatic removal of feeders was broken.
72			- (libeio) use a more robust method to detect whether a feeder
73			has added something to the group or not.
74
75	root	1.170	3.1 Thu Oct 2 13:34:40 CEST 2008
76	root	1.168	- pre-deref the passed callback object, for increased speed
77			and decreased memory usage.
78	root	1.167	- call on_next_submit callback even for aio_group - impact unknown,
79	root	1.166	but seems more correct.
80	root	1.168	- $req->cb now returns the original callback.
81	root	1.166	- (libeio) pass EIO_GROUP/aio_group requests through the queue without
82			requiring a thread switch.
83	root	1.169	- (libeio) status code of aio_futime and aio_utime was always passed 0.
84	root	1.166	- do some other µ-optimisations.
85
86	root	1.165	3.07 Sat Aug 2 16:06:13 CEST 2008
87			- do not include LIBS in autoconf tests.
88
89	root	1.164	3.06 Tue Jul 15 12:41:32 CEST 2008
90	root	1.162	- move preadwritelock definition before it's first reference,
91	root	1.164	to make it compile again on broken platforms (they still exist)
92			or badly cofngiured perls (redhat...), reported by Rob Bloodgood.
93	root	1.162
94	root	1.161	3.05 Thu Jun 19 23:23:52 CEST 2008
95	root	1.160	- work around perl overriding readdir etc. with thread-unsafe
96	root	1.161	(sic!) versions.
97	root	1.160
98	root	1.159	3.04 Wed Jun 18 01:35:38 CEST 2008
99			- (libeio) fix eio_mknod, which confused it's arguments.
100	root	1.158	- (libeio) do not use readdir_r, as Ulrich Drepper pointed out that this
101			is stupid.
102	root	1.159	- (libeio) fix eio__readahead prototype, patch by Jost Krieger.
103			- (libeio) fix a bug that could potentially cause IO::AIO
104			not to get initialised properly.
105	root	1.158
106	root	1.157	3.03 Thu May 29 05:33:30 CEST 2008
107	root	1.153	- (libeio) correctly call pthread_attr_destroy ().
108	root	1.155	- (libeio) work around broken bsd headers once more.
109	root	1.154	- reduce shared library size again by not including wrappers.
110	root	1.156	- max_outstanding could cause poll to enter a busy-waiting loop.
111			- document the new IO::AIO::poll_cb result value.
112	root	1.153
113	root	1.152	3.02 Mon May 12 02:32:02 CEST 2008
114	root	1.150	- fix a memory leak on aio_readlink.
115			- bring back working fchmod.
116	root	1.151	- nop and busy now set result to 0.
117			- set errno to ENOMEM when allocation fails.
118	root	1.150
119	root	1.149	3.01 Sun May 11 03:07:03 CEST 2008
120			- (libeio) make it compile on systems without readahead or readdir_r.
121	root	1.148	- (libeio) improve configure check for readahead availability.
122			- do not try to link against -lrt.
123	root	1.147	- use a separate configure script for IO::AIO (not the libeio one).
124
125	root	1.146	3.0 Sun May 11 00:57:14 CEST 2008
126	root	1.145	- added bin/treescan to the distribution.
127			- switched to using libeio.
128			- LOTS OF INCOMPATIBLE CHANGES:
129			- remove signal functionality, it is not worth the effort.
130			- max_outstanding no longer returns the previous number of requests.
131			- poll_cb no longer returns number of requests.
132	root	1.143
133	root	1.142	2.62 Sat Apr 26 13:59:33 CEST 2008
134	root	1.141	- port to solaris perls configured for old posix
135			(analysed by Jost Krieger).
136	root	1.142	- keep a reference to the perl filehandle object in aio_close,
137			so it doesn't get closed prematurely, leading to ugly races.
138	root	1.141
139	root	1.140	2.61 Wed Apr 16 18:45:02 CEST 2008
140	root	1.137	- fix treescan output duplication and improve output ordering.
141			also display files given on the commandline.
142	root	1.140	- use a different algorithm for aio_close that is faster
143			and probably has even lower chances of blocking.
144	root	1.138	- do our own stack memory management for threads - linux
145			allocates outrageous amounts of VM (not so bad unless you
146			use mlockall...), which severely limits the number of threads
147	root	1.139	on 32-bit arches: stack size is the larger of PTHREAD_STACK_MIN
148			and 4096 * sizeof (long) (usually this is 16..64k).
149	root	1.137
150	root	1.136	2.6 Sun Mar 30 08:28:11 CEST 2008
151	root	1.134	- added aio_sync.
152	root	1.135	- added aio_pathsync.
153	root	1.136	- fix prototypes of (void) functions.
154	root	1.134
155	root	1.133	2.51 Sat Oct 6 16:04:54 CEST 2007
156			- perlio isn't generally threadsafe, so aio_close could not work reliably.
157			aio_close now tries a safe hack that might not be that asynchronous
158			(see the manpage for details).
159			- discard callback return values as to not grow the stack endlessly
160			when poll_cb handles many requests without returning.
161			- minor code cleanups.
162
163	root	1.132	2.5 Thu Oct 4 14:49:08 CEST 2007
164	root	1.131	- replaced _fd2fh with faster xs code.
165			- aio_close will now try to do "the right thing" and thus might
166			work sensibly for the very first time.
167
168	root	1.130	2.41 Mon Sep 24 21:28:21 CEST 2007
169	root	1.129	- after fork, invest some work to make sure that the poll_fileno
170			stays stable (by dup2'ing the new fd over the old one), to make
171			it easier for programs/libs that don't control their forking
172			behaviour and cannot recreate their watchers.
173
174	root	1.128	2.4 Sun Aug 5 18:44:22 CEST 2007
175	root	1.127	- add aio_truncate, aio_chmod, aio_chown, aio_utime (linux
176			successfully demonstrated that you can block on futimes...).
177	root	1.124	- allow undef as fileoffset for aio_read/write and use read/write(2)
178			internally (useful for sockets or O_APPEND handles).
179	root	1.126	- allow undef for length in aio_write.
180			- negative dataoffsets work as expected now in aio_read/aio_write.
181	root	1.124	- use NV instead of UV for 32 bit perls and file offsets, as NVs
182	root	1.125	have a larger range then.
183	root	1.120	- shared code between BDB and IO::AIO.
184	root	1.127	- aio_busy was completely broken. now fixed.
185			- readahead emulation now returns something.
186	root	1.121	- correctly set errno to ENOSYS on unimplemented functions
187			(should never happen, though).
188	root	1.127	- large changes to make it partially compile and run on win32,
189			but win32 lacks too much functionality, and perl overrides way
190			too many functions with crashing versions.
191	root	1.120
192	root	1.119	2.33 Tue Jan 23 23:55:41 CET 2007
193			- fix install path (Andreas J. Koenig).
194
195	root	1.118	2.32 Mon Jan 22 16:56:23 CET 2007
196	root	1.114	- added aio_rmtree.
197	root	1.115	- wow, aio_mkdir was missing.
198	root	1.116	- aio_load did return undef on error, not -1.
199	root	1.117	- use prefixexp not prefix in autoconf.pm
200			(suggested by ... rt.cpan.org unreachable).
201	root	1.118	- avoid installing autoconf.pm.
202	root	1.114
203	root	1.113	2.31 Sat Jan 6 03:46:02 CET 2007
204	root	1.112	- added aio_load.
205
206	root	1.111	2.3 Sat Dec 23 05:48:07 CET 2006
207			- fix off-by-one bug in aio_read, causing memory corruption
208			or crashes.
209
210	root	1.110	2.21 Fri Dec 22 05:03:38 CET 2006
211	root	1.108	- minor doc updates.
212	root	1.107	- minor cleanups.
213			- IO::AIO::poll returns request count.
214	root	1.109	- undocumented and unfinished async-signal-reporting.
215	root	1.107
216	root	1.103	2.2 Tue Oct 31 00:31:00 CET 2006
217	root	1.100	- minor doc updates.
218	root	1.101	- added aio_readlink.
219			- properly zero-terminate aio_read buffer.
220			- fix aio_read/write with nonzero dataoffset.
221	root	1.104	- reduced size of aio request structure.
222	root	1.106	- better diagnostics when pathnames etc. are not byte-encoded;
223	root	1.105	do not leak request in that case, either.
224	root	1.94
225	root	1.99	2.1 Sun Oct 29 02:01:57 CET 2006
226	root	1.98	- INCOMPATIBLE CHANGE: replace IO::AIO::poll_some by
227			IO::AIO::max_poll_reqs and IO::AIO::max_poll_time.
228	root	1.95	- fix a bug in aio_move where it would fail everytime
229			it would have to copy files manually.
230	root	1.98	- doc updates.
231	root	1.94	- start threads only on (very low) demand.
232	root	1.97	- end superfluous threads automatically after 10s idling.
233	root	1.98	- add IO::AIO::max_idle to control this.
234	root	1.94	- some tuning applied to random places.
235	root	1.95	- add aio_mknod.
236	root	1.59
237	root	1.92	2.0 Thu Oct 26 18:27:58 CEST 2006
238	root	1.90	- minor incompatibility: max_outstanding semantics have changed.
239	root	1.86	- major rewrite, consider all functionality EXPERIMENTAL.
240	root	1.68	- aio requests can be cancelled.
241	root	1.81	- callbacks can be (re-)set later.
242	root	1.93	- aio requests can choose between 9 priorities.
243	root	1.83	- add aio_group: aio requests can be grouped
244			into composite requests.
245			- generator interface for groups.
246	root	1.89	- add IO::AIO::poll_some.
247	root	1.72	- major documentation improvements.
248			- very minor bugfixes.
249	root	1.76	- add aio_nop for dummy requests.
250	root	1.84	- add aio_busy mainly for benchmarking and debugging.
251	root	1.79	- use "fast" mutexes on linux.
252	root	1.80	- use dynamic (and larger) buffers instead of
253			putting them onto the stack.
254			- optimise x86 and amd64 a bit.
255			- better error checking when ENOMEM.
256	root	1.85	- hopefully fix mem and dirp leaks on fork.
257	root	1.92	- warn about broken perl malloc.
258	root	1.88	- compiles on cygwin (but pread is broken on cygwin
259			which is not detected by autoconf, so you have to
260			edit autoconf/config.h yourself to enable emulation).
261	root	1.68
262	root	1.67	1.8 Sat Jun 24 22:20:44 CEST 2006
263	root	1.66	- add and/or document aio_rename, aio_link, aio_symlink and aio_move.
264
265	root	1.65	1.73 Wed Mar 1 22:49:32 CET 2006
266			- codename "jost"
267			- AIX/Solaris(?) aren't being helpful again, hardcode a value
268			for NAME_MAX and drive with your eyes closed (reported by
269			wcooley@nakedape.cc).
270	root	1.63
271	root	1.62	1.72 Thu Feb 2 00:40:44 CET 2006
272	root	1.61	- another minor bug in aio_scandir, again, the callback was called
273			twice when the directory can't be stat'ed.
274
275	root	1.60	1.71 Mon Dec 26 20:20:03 CET 2005
276			- grr, another minor bug in aio_scandir, this time resulting
277			in a runtime error.
278
279	root	1.59	1.7 Mon Dec 26 19:29:48 CET 2005
280	root	1.58	- aio_scandir errornously called callback twice in some cases.
281	root	1.57	- added AnyEvent example.
282
283	root	1.55	1.61 Wed Sep 7 19:40:42 CEST 2005
284	root	1.54	- no longer include $Config{libs}, as distros include too much
285	root	1.56	garbage in there that is not installed on typical systems
286	root	1.54	(for example, debian links perl against -lgdbm and many more
287			libraries despite perl not needing it, slowing down startup and
288			wasting memory).
289
290	root	1.53	1.6 Tue Aug 30 17:44:44 CEST 2005
291			- added aio_readdir, aio_scandir.
292	root	1.51	- added aio_sendfile, including sendfile emulation when sendfile
293			isn't available. Linux, FreeBSD and HP-UX might work (sendfilev
294			support is unavailable on my solaris 8 machine, but preliminary
295			code is there. What's lacking is configury stuff and testing...).
296	root	1.46
297	root	1.44	1.5 Sat Aug 20 02:32:19 CEST 2005
298	root	1.51	- create the aio threads on demand only (good after forking).
299	root	1.41	- somebody nagged about C89 compatibility, so this release should
300	root	1.42	be C89 compatible, but no guarantees for future ones.
301	root	1.43	- abort when the configure script fails.
302	root	1.41
303	root	1.40	1.4 Wed Aug 17 08:07:27 CEST 2005
304	root	1.93	- forgot to recreate the pipe after forking, this could cause
305	root	1.40	deadlocks.
306
307	root	1.39	1.3 Wed Aug 17 07:25:54 CEST 2005
308	root	1.33	- properly propagate exceptions from callbacks, instead of silently
309			eating them.
310	root	1.38	- use a different fork algorithm that avoids recursive callback
311			invocations and reduces fork latency in busy processes.
312	root	1.37	- fix a bug where the buffer scalar in aio_read got assigned the wrong
313			length after reading.
314			- fix a bug where the child would process some outstanding requests
315			from the parent.
316			- make a copy of the callback scalar, to avoid some very uncommon
317			(but valid) usages where the callback scalar changes.
318			- the callback was never freed in aio_read/aio_write.
319	root	1.38	- aio_read/aio_write will now set the readonly flag on the data
320			scalar for better error reporting.
321	root	1.33
322	root	1.32	1.2 Wed Aug 17 01:22:58 CEST 2005
323			- verified on cygwin, linux/amd64+ia32+alpha, solaris.
324	root	1.31	- use SvPVbyte for filenames now. You need to encode your strings to
325			the external filename encoding first.
326	root	1.32	- fix the bug where filehandles could leak (again).
327	root	1.31	- clarify freebsd situation: make it work and tell me how, or go away
328			with your underdocumented, broken and outdated OS.
329			- fork'ing should now be officially supported (where linux and
330			posix contradict each other, I followed posix).
331	root	1.32	- only call read() once per poll, not twice (speedup).
332			- new functions: aio_rmdir, aio_symlink.
333	root	1.31	- force callback arguments to be undef or a reference, for better
334			error catching.
335	root	1.1
336	root	1.29	1.1 Sun Aug 7 05:27:23 CEST 2005
337	root	1.25	- added configure script to detect availability of some calls.
338	root	1.27	(imperfect, as we cannot detect things like -lrt due to missing
339	root	1.23	feedback yet).
340	root	1.27	- emulate fdatasync via fsync, pread/pwrite via unsafe read/write
341			and readahead via manual reading on platforms lacking those.
342	root	1.19	- ported t/03_errors.t+framework by Brad Fitzpatrick
343			from Linux::AIO.
344	root	1.18	- removed XOPEN_SOURCE because stupid solaris 9 doesn't
345			compile with it enabled. Probably breaks others. Oh well.
346	root	1.24	- try to be more careful with errno on non-threaded perls.
347	root	1.26	- cygwins perl insisted on a matching open mode when morphing
348			the fd to an fh.
349	root	1.28	- convert sv's to "byte" encoding in aio_read/aio_write. Might
350			do that for pathnames, too, in the future, so make sure you
351			properly encode your pathnames.
352	root	1.18
353	root	1.17	1.0 Fri Jul 22 10:43:30 CEST 2005
354			- aio_open did not reliably deliver (open) filehandles.
355	root	1.16	- all aio_*-functions keep a reference to the filehandle so
356			it doesn't go away while the aio requests is working on it.
357			- disable warnings in AIO.pm.
358
359	root	1.15	0.9 Wed Jul 20 23:55:04 CEST 2005
360			- allow recursive calls to poll_cb, use less locking calls, too.
361			- fix the Gtk2-example in the SYNOPSIS.
362	root	1.14	- use pread/pwrite not pread64/pwrite64. this was simply a leftover
363			from Linux::AIO.
364			(found by compiling on cygwin. Unfortunately, cygwin declares but
365			does not implement pread/pwrite).
366			- only include <sys/syscall.h> on linux.
367
368	root	1.13	0.5 Tue Jul 12 13:03:09 CEST 2005
369	root	1.12	- removed #include <endian.h>, it's not portable, and we don't
370			need it anyway.
371			- link against -lrt, as it might contain goodies such as fdatasync,
372			and often aio_read, which we do not use yet, but it shouldn't hurt.
373
374	root	1.11	0.4 Mon Jul 11 05:28:25 CEST 2005
375	root	1.9	- added IO::AIO::flush, IO::AIO::poll.
376	root	1.10	- make callback argument optional for all calls.
377	root	1.8
378	root	1.7	0.3 Mon Jul 11 01:42:37 CEST 2005
379	root	1.5	- restructured manpage.
380	root	1.7	- added SYNOPSIS with examples for Event, Glib, Tk.
381			- remove explicit context support so I don't have to maintain
382			it for threaded perls (i.e. it should work now :).
383	root	1.5
384	root	1.4	0.2 Sun Jul 10 22:57:12 CEST 2005
385	root	1.2	- return immediately from poll_wait if nreqs==0.
386			- get rid of the request pipe and use faster thread-thread
387	root	1.3	communications for most requests and responses.
388	root	1.2
389	root	1.1	0.1
390			- cloned from Linux::AIO, which is very similar.
391