On Wed, Aug 28, 2002 at 02:50:55AM -0300, Paulo Alexandre Pinto Pires wrote:

 > 	USER     PID %CPU %MEM   VSZ   RSS TT STAT STARTED    TIME COMMAND
 > 	pappires 562  0.0  0.0    72    72 p2 S+    1:55AM 0:00.00 ./test-static 
 > 	pappires 565  0.0  0.1    16   340 p2 S+    1:55AM 0:00.00 ./test-shared
 > 
 > 
 > ps(1) shows a resident segment size for the shared version almost five
 > times as large as that of the static version.  The virtual space, on
 > the other hand, is 4.5 times smaller.
 > 
 > Which one matters?  Does RSS count shared pages multiple times, for
 > each process that depends on a shared library (here, only libc)?

A couple of things are happening:

	(1) Some pmap modules count page tables as "resident" pages.

	(2) The resident page count is actually a count of page mappings,
	    and so shared pages are, in fact, being counted multiple times.

In fact, an all-dynamic system is likely to save memory, since e.g. there
won't be multiple copies of the stdio code in memory.

-- 
        -- Jason R. Thorpe <thorpej@wasabisystems.com>