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From: "jb at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug libfortran/25830] [libgfortran] Optionally support multi-process locking Date: Mon, 25 Apr 2011 16:41:00 -0000 [thread overview] Message-ID: <bug-25830-4-FAe9J3Vzl1@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-25830-4@http.gcc.gnu.org/bugzilla/> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25830 --- Comment #4 from Janne Blomqvist <jb at gcc dot gnu.org> 2011-04-25 16:41:26 UTC --- Some writings arguing that POSIX locking is more or less fundamentally broken: http://0pointer.de/blog/projects/locking.html http://0pointer.de/blog/projects/locking2.html http://www.samba.org/samba/news/articles/low_point/tale_two_stds_os2.html AFAICS, if gfortran is to eventually support multi-image IO in the context of Co-array Fortran as in the TR http://j3-fortran.org/doc/meeting/192/10-166.pdf , it is possible to implement all of this without relying on POSIX locking (fcntl) for synchronization, instead using the existing IPC channels that co-arrays provide. That being said, it might be necessary to do a fcntl lock+unlock at appropriate places in order to force the NFS client to flush dirty bytes to the server; alternatives to using fcntl() to force NFS flushing is fsync or a close+reopen of the POSIX file descriptor. Close+reopen does have the nice property of being portable and not relying on a working NFS locking implementation. FWIW, one strange thing about the 10-166 TR is that there is no mention of stream access, which AFAICS is suited to parallel access just like direct access.
next parent reply other threads:[~2011-04-25 16:41 UTC|newest] Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <bug-25830-4@http.gcc.gnu.org/bugzilla/> 2011-04-25 16:41 ` jb at gcc dot gnu.org [this message] 2020-04-21 9:45 ` cvs-commit at gcc dot gnu.org 2006-01-17 22:06 [Bug libfortran/25830] New: " jb at gcc dot gnu dot org 2006-01-17 22:07 ` [Bug libfortran/25830] " jb at gcc dot gnu dot org 2006-01-17 23:33 ` pinskia at gcc dot gnu dot org 2008-11-20 15:53 ` burnus at gcc dot gnu dot org
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