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From: jonasn@ttds.UUCP (Jonas Nygren)
Newsgroups: comp.windows.x,comp.unix.ultrix
Subject: DEC3100-Xlib performance
Message-ID: <1201@ttds.UUCP>
Date: 17 May 89 21:43:16 GMT
Reply-To: jonasn@ttds.UUCP (Jonas Nygren)
Organization: The Royal Inst. of Techn., Stockholm
Lines: 31

When trying out X on a DEC3100 with dxwm, DEC's window manager, I ran a small 
program which drew arc's in a window, and I was astonished by the speed, or 
rather the lack of speed. In a 300 by 300 window the following code was 
executed (monochrome, only Xlib, after necessary initializations):

			t = time(0L);
			for(i = 5; i < 3000; i += 10)
				XDrawArc(disp,win,gc,0,0,i,i,90*64,90*64);
			
			XSync(disp,0);
			printf("Time: %ld s.\n",time(0L) - t);

The time reported was 238 s !!! Is this fast or slow in X-reality?? I tried out
the same code on a Mac (using Mac-OS, Quickdraw etc, NOT X) and with the same
window size and the same for-loop the measured time was 32 s !!! 

The DEC3100 is approx 20-25 faster than my MacPlus on integer operations which
indicates that the Mac is approx 140 (238/32 * 20) times more efficient than
the DEC3100 regarding this graphic test. Could anybody tell me what is
happening in the X-code ???

When I tried to break this test with ^C's I found out that the system no longer responded, indicating that the X-server had some abnormal priority. Is such
a behaviour normal when running X standalone on a workstation or is this 
something DEC-specific ??? Is there anything I could do to alter this ???

/jonas

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Reply-To: jonasn@ttds.UUCP (Jonas Nygren)
Organization: The Royal Inst. of Techn., Stockholm