Re: [AD] Some findings of using Allegro on a multi-processor machine.

[Hein Zelle <hein@xxxxxxxxxx>]

AE wrote:

> I later read a discussion here about Allegro having difficulties on
> multi-processor machines. "This was it", I thought. I remembered
> that my friend's machine was the only machine I had tried it on that
> had a motherboard that could support multiple CPUs (I wasn't
> entirely sure if there really was >1 CPU, but then again, Windows 98
> may not be able to recognise a second CPU), and I was pretty sure
> that the other machines I had tried it on were only single-CPU.

I don't know if this goes for all multi-processor systems, but for
this one (linux) the symptoms are crashing GUI programs, not input
disappearing or hanging programs. The grabber just crashes and dies.

I do know allegro did NOT have these problems when the machine only
had one CPU before, so it's definitely only relevant if there really
are 2 CPU's in there. I don't know what happens with 2 cpu's and an OS
that only recognizes one, I would think the problem would disappear.

Finally, if you do run into multi-cpu problems, Eric mailed recently
that the only fix is to compile with --disable-pthreads on linux (make
a single threaded version). I don't know if that's even possible on
windows, or if it would fix things there.

> One thing that does strike me as strange is that although Windows 98 SE only
> makes use of one processor, the problem still showed up.

Which probably means it's caused by something else.

> Anyway, I found that the only version that demonstrated the problem was the
> first version (the fullscreen 4.1.x version (GFX_DIRECTX) ). All 4.0.3
> versions ran fine, as did all windowed versions (GFX_DIRECTX_WIN and
> GFX_GDI).

And that definitely suggests it has nothing to do with multiple CPU's,
but with the fullscreen DIRECTX driver. Perhaps something like this
has been fixed in 4.1.12, other people can probably answer that.

Hein Zelle

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 Hein Zelle                     hein@xxxxxxxxxx
	                        http://www.icce.rug.nl/~hein
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