[Caml-list] Threads - how it actually works?

[Caml-list] Threads - how it actually works?

[Michał Maciejewski]

Hi,

Some time ago I had some problems with threads. I had to make a
traffic lights simulation with cars as a academic project. I decided
to write it using ocaml with graph module and threads for timing
(since thread pausing didn't work in the same thread that the graph
module worked). If I remember correctly there was a loop in graph
module thread that was drawing some objects. Another looped thread was
changing objects positions and then was paused for some amount of time
using (I think) Unix module. I know that wasn't a good and optimal way
to do it, but I had only few days for it.

Now the problem was that one of those thread never worked. It looked
like a graph thread was using whole cpu time, and there was no context
switching. Don't ask me to paste any code, because I dont have it. It
was quite long time ago and I had to do my project without timing. :-)
It was ocaml 10.*. So how threads are actually implemented in caml?
Using some kind of timing or atomic operations?

regards
M

Re: [Caml-list] Threads - how it actually works?

[Philippe Wang]

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if you have a thread that never allocates any value in the memory heap, then
the thread may prevent the GC from working properly...



2009/6/27 Michał Maciejewski <michal.m.pl@gmail.com>

> Hi,
>
> Some time ago I had some problems with threads. I had to make a
> traffic lights simulation with cars as a academic project. I decided
> to write it using ocaml with graph module and threads for timing
> (since thread pausing didn't work in the same thread that the graph
> module worked). If I remember correctly there was a loop in graph
> module thread that was drawing some objects. Another looped thread was
> changing objects positions and then was paused for some amount of time
> using (I think) Unix module. I know that wasn't a good and optimal way
> to do it, but I had only few days for it.
>
> Now the problem was that one of those thread never worked. It looked
> like a graph thread was using whole cpu time, and there was no context
> switching. Don't ask me to paste any code, because I dont have it. It
> was quite long time ago and I had to do my project without timing. :-)
> It was ocaml 10.*. So how threads are actually implemented in caml?
> Using some kind of timing or atomic operations?
>
> regards
> M
>
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-- 
Philippe Wang
  mail@philippewang.info

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