Re: Memory statistics

[Federico Mena Quintero <federico ximian com>]

On Tue, 2006-04-18 at 19:52 +0200, Beno�Dejean wrote:

> import os
> import gtop
> 
> for pid in gtop.proclist(gtop.PROCLIST_KERN_PROC_UID, os.getuid()):
> 	gtop.proc_map(<pid>)

/me self-slaps for reinventing the wheel :)

Some quick numbers from a bit of grep/awk action on the results:

- The private_dirty for libraries is under 14 MB on my box.  This is
much smaller than the heaps for fat apps (i.e. hundreds of MB for
Evolution/Mozilla).  So, reducing .data and friends is probably
interesting only for embedded devices.

- We have a lot of mappings that are exactly 8192 KB.  This is the
default stack size for threads.  Most of those mappings are clean (few
or none pages committed to memory), which means that threads have
smaller requirements for their stack size than the default.  Still, this
looks bad in top(1) and in pmap :)

- All GTK+ apps which display images have about 700 KB of shared memory
segments, used for MIT-SHM with the X server.  The segments are totally
private_dirty.  Could we free the segments if they haven't been used in
N seconds?  Could we only start using them until we have to transfer a
big image to the X server?  Transferring icons is probably fast enough
over the normal Unix domain socket.  For my session, the shm segments
occupy about 6 MB in total --- again, probably more useful for embedded
devices than for desktop boxes.

  Federico