[Xquartz-dev] glxgears performance differences in rooted/rootless window

[Dave Ray]

On Nov 10, 2008, at 2:14 PM, Jeremy Huddleston wrote:

> There should really be no difference in GLX performance between  
> fullscreen and rootless... there may be some slight performance  
> issues due to window compositing which doesn't happen if you're in  
> fullscreen (because the root window blocks the other windows)... I  
> think this is when the mouse cursor is near the dropshadow of the  
> window ... or maybe when the drop-shadow of another window is near  
> the window... something like that... I don't exactly recall (sorry).

I tried to position the window for glxgears well away from any other  
windows, and the mouse was far away not being moved. So I was  
surprised to see the big change in frame rate. Curious if you compared  
the glxgears frame rates on your system between fullscreen and  
rootless mode? If they don't vary much on your system then perhaps I  
should suspect my wm.

> As for the "visible in rootless mode" then cmd-alt-a into  
> fullscreen, I'm confused... are you running in rootless or  
> fullscreen mode?  If you have fullscreen enabled, then you shouldn't  
> see any window in rootless mode.  It should pop up in X11- 
> fullscreen, but what it should do and what it does do are sometimes  
> not quite right with new features... ;)

I am running in fullscreen mode, but since the command-tab isn't  
currently active in X11, the only way I can get out of X11 is to  
option-cmd-A, and then command-tab. So I'm not sure what state that  
leaves X11. I am using full screen mode but escaped it using option- 
cmd-A, before going to Terminal and running the programs.

> What is the state of your "Focus on new windows" option?

"Focus on new windows" is checked, "focus follows mouse" is un-checked.

I guess I was confused to see the window first appear against the  
Apple desktop when I thought X11 was in fullscreen mode. When I tried  
this under Apple's stock X11 from 10.5.4 I don't remember seeing  
this,m i thought new X11 windows were always drawn off-screen in the  
X11 root window.

I just re-tested this and it is still happening, the window shows up  
initially on the Apple desktop and I can still reproduce that.

I am observing a slight difference in the sequence of events from my  
last post. When I launch any X11 app from Apple Terminal with X11  
running in the background (fullscreen mode), the window shows up in a  
window against the Apple desktop, while Terminal is still in the  
foreground. It sort of looks like rootless mode with X11 in the  
background. As soon as I switch to X11 with command-tab or by clicking  
on the X11 app's window, the screen goes to X11 fullscreen mode and  
the newly created window is there in the X11 root window as expected.  
This is a change from what I saw yesterday. When I switch out of  
fullscreen with option-cmd-A, the window is no longer on the Apple  
desktop in the background, as I would expect, it remains bound to the  
root window. I tested it twice before my post yesterday, so I'm pretty  
sure something changed. Aaargh. I guess I can still do the glxgears  
frame rate comparison by manually switching X11 in and out of  
fullscreen mode.

But in both yesterday and today's cases, the window shows up initially  
on the Apple desktop and I can still reproduce that, which is the  
thing you were concerned about.

Dave


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