Re: New bug: flock not implemented -> sem fails

[Ole Tange]

On Thu, Nov 10, 2011 at 12:41 AM,  <parallel-bugs@pkts.ca> wrote:

> I'm trying to install parallel 20110822 on a lustre filesystem, and
> apparently it does not support flock() by default, and the system call
> dies with:
>
> lock(7, LOCK_EX|LOCK_NB)         = -1 ENOSYS (Function not implemented)
>
> Reference:
> http://wiki.lustre.org/index.php/FAQ_-_Fundamentals see 'flock'
>
> This is a little vexing, as the makefile is just converting pod files
> to html, although I guess it's a clever way to run unit tests during
> the installation process:

Unfortunately it is not a clever way to do testing. The problem is
that pod2html uses a temporary file that I cannot control the name of.
If you run multiple pod2html's in parallel then they will overwrite
this temporary file and cause the installation to fail randomly. This
will happen when running:

  make -j

which people/packaging systems apparently do.

I assume you have access to at least one writeable dir that supports
flock (maybe /dev/shm or /tmp?). You can then just move your
~/.parallel to this place and symlink it to ~/.parallel before running
make.

> Will parallel work without flock?

Yes, except for the --semaphore functionality.

The locking happens around line 4894. If you find an alternative way
to support locking on Lustre, let me know.


/Ole