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From: larryc@puente.jpl.nasa.gov (Larry Carroll)
Newsgroups: comp.windows.x
Subject: Impact of Running Several Large X Programs
Message-ID: <1991Apr30.024458.1020@jpl-devvax.jpl.nasa.gov>
Date: 30 Apr 91 02:44:58 GMT
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We have an Ethernet network of a bunch of DECstation 3100s running X & 
Motif.  Currently the X is DEC's DECwindows, which is X11R3 (or so I'm 
told), but we're soon migrating to a generic X11R4.  There's also a 
VAX with about a gigabyte of disc space that we'll use to store raster
maps.  All systems run Ultrix & are NFS'd together.

For some reason I don't fully understand, the lead designer wants to allow
users to launch as many copies of a map-viewing & -annotating program as 
they choose to.  I wonder at the impact on performance this is likely to 
have -- each of the the map programs runs at least 5 MBytes, & when we're 
done enhancing them I'd guess they'll end up 8-10 MBs, or even larger.

Since there's only (!) 16 MBs of RAM, it seems likely that more than 
one copy of this large program is likely to cause disc thrashing, especially 
since users are likely to also have windows up with a mail handler, word 
processor, and a few other such utilities.

My question is: where can I get some studies on this problem?  What tools 
can I use to measure performance?  And (for anyone with a pipeline to 
tomorrow!) are there any enhancements to Ultrix (such as shared libraries) 
or X Windows that we can expect anytime soon that will improve performance?