Re: [Caml-list] f#/mono vs ocaml runtime system - open gl animation screen tearing.

[Gabriel Scherer <gabriel.scherer@gmail.com>]

[-- Attachment #1: Type: text/plain, Size: 2950 bytes --]

Given the complexity and general fragility of the graphic stack on
GNU/Linux, I would suppose this issue can come from anywhere. It may be
related to the GC pauses (and the difference in GC behavior might be mainly
correlated to boxing/unboxing decisions), but it may as well come from a lot
of other things. Are you positive the language runtime system is the only
change between your two setups ? For example, would a simple animation
written in C and OCaml and F# perform differently ?
It may also be an issue with the OpenGL FFI binding (I would trust the OCaml
GC more than a hairy mix of OCaml/C code binding a large library).

I have absolutely no expertise in this domain, and your initial idea may
very well be correct, but still you should make sure you're really
investigating the real problem, and not something completely unrelated,
before going into something as specialized and difficult than runtime
implementation considerations.

On Tue, Apr 26, 2011 at 9:15 PM, Peter Ronnquist
<peter.ronnquist@gmail.com>wrote:

> Hi all,
>
> I have been experimenting with f# and mono on debian linux and
> compared it with ocaml.
> I am interested in visual presentations for example games and in my
> tests f# + mono + opentk was able to make completely smooth animations
> using opengl (opentk) on debian 6.0 (squeeze).
>
> Ocaml + lablgl gives "stutters" in the animation within the period of
> a couple of seconds. The animation runs smooth for a couple of seconds
> and then the animation update is disturbed with the result that the
> image is "teared". The tearing lasts only for a fraction of second but
> is visible for a trained eye.
>
> I suspected that the GC could be a cause for this and I tried to
> manipulate the GC settings but I could not get a completely smooth
> animation for a longer period of time.
>
> This is completely acceptable for many applications but for making a
> game or for the meticulous graphical applicaton user it is not ideal.
>
> My thought is that maybe f#/mono unboxes more values than ocaml and in
> this way the GC doesn't need to work as hard?
>
> My question really is if you think it is worthwhile to investigate the
> runtime system for mono and compare it with the runtime system for
> ocaml to locate the differences that might influence the animation and
> then even update the ocaml runtime system to use a similar strategy
> as the f# runtime system?
>
> I would be interested in this but it would be nice to first hear from
> the list if this is a good idea. I also read in the Jane Street blog
> (http://ocaml.janestreet.com/?q=node/89) that ocamlpro might work on
> the ocaml runtime system (including unboxing).
>
> Best Regards
> Peter Ronnquist
>
> --
> Caml-list mailing list.  Subscription management and archives:
> https://sympa-roc.inria.fr/wws/info/caml-list
> Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
> Bug reports: http://caml.inria.fr/bin/caml-bugs
>
>

[-- Attachment #2: Type: text/html, Size: 3696 bytes --]