problem with opengl (glxgears) running on cygwin ....

Linda Walsh cygwin@tlinx.org
Tue Mar 25 15:59:00 GMT 2014


Jon TURNEY wrote:
> Since [1], glxgears turns at a constant 70 degrees per second.
---
70 degress/s?  How is that important?


> 
> glxSwapBuffers does not block when used with indirect rendering, which means
> that lots of frames can be rendered almost instantly, with no apparent
> rotation, since the elapsed time between frames is very small.
----
	According to the text in the starting window it is rendering at
30FPS.  -- I.e. it is sync'ed with my monitor's refresh rate (except
for the 1st iteration when it acted unsynced)....
... I.e. in starting window this was displayed:

Running synchronized to the vertical refresh.  The framerate should be
approximately the same as the monitor refresh rate.
45623 frames in 6.4 seconds = 7166.903 FPS
834 frames in 27.4 seconds = 30.428 FPS
822 frames in 28.8 seconds = 28.542 FPS
----
With all X-window response degraded (Xserver process was peg'ed@100%cpu),
virtually no network traffic -- dropped from a norm of 200-400KB/s down to
between 1KB-80KB/s.


> glxgears is a very basic test that GLX is functioning, and definitely not a
> benchmark.  Real GLX clients should have a better mechanism for ensuring their
> animation rate doesn't outrun the vsync frequency.
----
I thought it was the most basic.  It claims (except for the 1st
iteration) that it is not outruning my monitor's refresh rate.


> 
> If you have any problems with real GLX clients, I would be interested to hear
> them.
----
I'd be interested in finding any that work and proves that
it works locally.  While my initial use was to try remote GLX,
I reverted to trying it localling -- just to verify it worked
as it used to.

Thats what brought this on.


> What is the OS of the remote system?
---
linux (opensuse 13.1).

No one else on that list was able to see normal response...
some got really sluggish response, others saw no movement or
nothing.

It was only after I ran glxgears locally that I figured I might
also have a problem in Cygwin's X, in addition to any other
problem I have w/remote display.


> I think this is because glxgears will send frames as fast as it can, and can
> saturate the X server.
----
The demo claims to sync at the same rate the monitor is refreshing.

i.e -- 30 FPS.


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