[lug] Re: X memory usage

[Scott Herod]

The question of X's memory usage comes up fairly regularly.  In fact, X 
itself uses no more than a megabyte or two (according to a talk by one of 
the developers at Linux World two years ago).  A fairly good thread on 
this topic went on at one of debian's lists referenced through

http://lists.debian.org/debian-x/2002/debian-x-200209/msg00098.html

A good comment is from Mike A. Harris of Red Hat Software:

"The memory shown by top, which users are misled into believing is memory
used up by X, is an amalgamation of the video card's own memory, and
memory mapped I/O regions, as well as the actual memory used by the X
server, pixmaps, and various other things.

"It is not at all uncommon for a modern 64Mb video card, to have X's
memory usage appear to be 100Mb or more, when in reality, 64Mb of that is
video RAM, and 16-32Mb possibly mmapped registers.

"On Linux a user can view the memory map breakdown by logging in as root
and looking at the file: cat /proc/$(pidof X)/maps"