[Caml-list] native threads not parallel?

[Markus Mottl <mottl@miss.wu-wien.ac.at>]

Hello,

I am having problems using native threads (under Solaris; don't know
about other architectures): I can't get them to run in parallel on a
dual-processor machine even though I turn off the master lock on the
C-side around an external function that should execute in parallel.

There are four threads running (I actually create two only - ?) as I can
observe with "ps -L". The two created ones reach the external Fortran
routine (in LAPACK) at about the same time, obviously in parallel or at
least interleaved up this point as I can see in the logged checkpoints.

I turn off/on the lock around this routine as in:

  enter_blocking_section();

    some_really_expensive_function ();

  leave_blocking_section();

Unfortunately, the expensive function is executed sequentially only.

What could be the cause of the lack of parallelism? Am I just
misunderstanding how things work? If this could be a bug, I can send
you more information to the bug-tracker, of course.

Regards,
Markus Mottl

-- 
Markus Mottl, mottl@miss.wu-wien.ac.at, http://miss.wu-wien.ac.at/~mottl
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