[cello-devel] High CPU load also on Linux!

Kenny Tilton ktilton at nyc.rr.com
Wed Mar 10 15:23:45 UTC 2004

Frank Goenninger wrote:

>After a bit of searching on WWW I found this bit of explanation:
>(An answer to a message complaining about high cpu usage when doing
>OpenGL stuff):
>I know that you are working with Win32.. and I have no clue about that..
>but heres why OpenGL often eats CPU on those examples you find on the
>net.. I suppose your examples are using the Glut.
>void idelCB(void) {
>... /* Do something */ ...
>glutPostRedisplay(); /* <= This should be the problem */
I am almost certain you will discover one of two things. Either:

(1) the window is being created with ":display-continuous t", which gets 
handled in mg-glut-display thus:

            (when (display-continuous *w*)
              (trc nil "mg-glut-display > posting redisplay w " *w* 

or (2), that the ix-render method for the window class ends with 

If so, the high cpu load is intentional (by me). The problem (on win32) 
becomes apparent when any such forced redisplay gets disabled. then the 
shapes stop spinning,eg, so you know the application-forced redisplays 
have stopped. At this point win32 still shows 100% cpu used by Freeglut, 
because of the rush job I found out about yesterday. Apparently I can 
get the fix by updating from the latest cvs on freeglut.

I have not noticed any discussion of the x11 side of things, so maybe 
once you disable the redisplays your cpu load will just drop. I am 
almost certain the patch I need to download is win32-only. so if you 
still see a blazing high cpu load we might have a problem.

Hey, congrats on the light panel and Cloucell! I just released those to 
the list, should be arriving soon.


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