[interfacekit] Re: :) Again - BBitmap

On Wed, 30 Jul 2003 08:43:52 +0300 "Adi Oanca" <e2joseph@xxxxxxxxxx> 
wrote:
[...]
> > > Is it more good at driver side? 'Cause
> > > IHO, it isn't - if app_server were to draw in off-screen bitmaps,
> > > then. no
> > > context switching would be done.
> >
> > I'm not sure, if I understand your reasoning. Are you trying to say
> > something like that, if all drawing is done by the app server, the
> > system would only need to switch between those? That assumes, that
> > virtually no other thread is ready to run at that time.
> 
>     No Ingo! All I'm saying is that, if we draw into bitmap app-side, 
> a LOT
> of context switching would be done, because, EVERY drawing 
> instruction form
> every window/app that is running at a certain time would require a 
> lock
> acquisition - from the driver.

I don't know, how graphic card drivers work, so I can't say much here. 
E.g. if the lock is only held for a very short time, then threads won't 
block too often on it.

[...]
> So, finally, can someone tell me, where will we draw our bitmaps?

Not that I would claim to have the final say...
Although I think, it would be more logical to draw non-off-screen 
bitmaps (you know the ones I mean ;-) on the application side, the 
printing issue Marc brought up would indeed be a bit ugly. Moreover I 
would trust his judgement as an intimate app server adept, that it 
would cause a lot more changes to be made than seems obvious. So, app 
server side drawing seems to be the way to do it for the time being. If 
the discussed idea to limit the number of threads for bitmap drawing is 
not too complex, I would say, implement it. Though, if Axel and/or 
Michael (or whoever) provide us with the functionality to set a 
thread's stack size, I would also find it completely OK to implement it 
like Be did (one app server thread per bitmap that accepts views) -- it 
will then still be better than what Be delivered and time for this kind 
of optimizations is after R1.

But anyway, that's just my opinion. It's certainly more a decision of 
the people involved in the app server development, and on dissens the 
one of the team lead.

CU, Ingo

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