Alan Cox <alan <at> lxorguk.ukuu.org.uk> writes:
> Vblank support is also possible but doesn't seem terribly useful.
Sorry for being gross off-topic.
But I see the vblank (the feature that lets the (whatever space) programs
know when the vertical return occurs ?) as a quite useful thing...
Because then the rendering rate is (supposed to be) limited to whatever
the monitor supports (say 60Hz, 1 frame every 15ms) it may be useful as a
comparision how much _free_ cpu time is left when the program
is ready for another frame, that including any (e.g. AI, engine or) system
tasks running (e.g. network communications, debugger)
IMvhO it so would be useful for tracing/profiling these apps, without
stress-testing and give you reproductible results for the performance
of your graphic engine... because there is plenty of time left
for everything else and it does not step on each others toes or turning
your machine into a (blow)heater :)
Just my thoughts.
L.
> But I see the vblank (the feature that lets the (whatever space) programs
> know when the vertical return occurs ?) as a quite useful thing...
Nothing much in the 2D world seems to use it for anything. In the 3D
world yes vblank syncing and page flipping is important, but the driver
is 2D only.
Alan
On Wed, Jun 08, 2011 at 01:24:49PM +0100, Alan Cox wrote:
> > But I see the vblank (the feature that lets the (whatever space) programs
> > know when the vertical return occurs ?) as a quite useful thing...
>
> Nothing much in the 2D world seems to use it for anything. In the 3D
> world yes vblank syncing and page flipping is important, but the driver
> is 2D only.
>
Video players probably want to use it to provide tear/stutter-free playback?
-- Pasi