[interfacekit] Re: :) Again - BBitmap

> >     But,... that's does not happen in app_server, all threads have
> > the same
> > team.
>
> Sure, but the threads of an application are in a different team. Hence
> there is at least one context switch between the invocation of a BView
> drawing method and the point when the actual drawing is finished. For
> synchronous requests there's at least another context switch before the
> application can continue.

    Aha. I finally understand what you mean by saying context switching.
That is thread switching - witch involves readying for execution with that
thread's data. Yes, one for drawing with app_server, none for drawing with
an accelerant.

> >     I'm talking about cloning accelerants. One for every application
> > that
> > uses off-screen bitmaps. Every one of them, have to wait for a lock
> > from the
> > driver. Isn't this context switching?
>
> When the thread tries to acquire an already locked mutex, then it is
> descheduled and another thread is scheduled. If the new thread belongs
> to another team, then a full context switch needs to be done.

    Yup. I got it! :-)

> > 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.

> Anyway, I still don't think, cloning accelerants in the applications is
> a good idea. It undermines the client/server approach and will make
> implementing support for running remote applications more complex.

    I don't think so either, because of the above reason and the one you
gave here.


So, finally, can someone tell me, where will we draw our bitmaps?


Adi.

Other related posts: