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Re: [Caml-list] native threads not parallel?
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Date: 2003-02-21 (17:58)
From: Markus Mottl <markus@o...>
Subject: Re: [Caml-list] native threads not parallel?
On Sat, 22 Feb 2003, Jacques Garrigue wrote:
> About the problem Markus is describing, and if he is using
> Thread.create as you suggest, I may see a cause.  Seeing that the code
> for caml_thread_new in posix.c contains no enter_blocking_section, if
> you create a thread with Thread.create, it will immediately block
> trying to get the caml mutex. It will get it eventually from the main
> caml thread through a yield, but a clever scheduler will schedule this
> thread on the same processor (it starts just when the previous one
> stops). As Markus says, after a long time the scheduler may realize
> this choice was wrong and change the processor, but this is scheduler
> dependent.
> I may be utterly wrong in my inference, but if this is right, a better
> solution would be to explicitely start the thread with pthread_start
> from the C side.

Thanks, this seems to be a good explanation for the strange behaviour
of native threads under Solaris. Maybe another solution would be to
set different scheduler flags, but I haven't read up on this, since our
Solaris machines are going to be replaced by Linux ones at our place.

Markus Mottl

Markus Mottl                                             markus@oefai.at
Austrian Research Institute
for Artificial Intelligence                  http://www.oefai.at/~markus
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