[sugar] some new matchbox rpm testing results

[Martin Dengler]

I ran into a discussion on #sugar about a new matchbox rpm from tomeu
with compositing enabled[1], and he asked me to email some testing
results to sugar@ - in particular, to determine the memory impact, and
whether that memory was in Xorg or the activities.

It looks like the memory is in Xorg[2], and is around 2 MiB per
activity[3]:

$ echo ; grep matchbox-window-manager: before after. ; for app
in matchbox olpc-upd python Terminal Browse Write Journal Xorg ; do
echo ----- ; grep $app before after.  | grep MiB; done

before:matchbox-window-manager: 1.2-3.20070628svn
after.:matchbox-window-manager: 1.2-3.20070628svn.fc7
-----
before:  1.4 MiB +   2.8 MiB =   4.2 MiB        matchbox-window-manager
after.:  1.5 MiB +   2.8 MiB =   4.3 MiB        matchbox-window-manager
-----
before:  3.0 MiB +   2.3 MiB =   5.3 MiB        olpc-update-que
-----
before: 52.2 MiB +  10.5 MiB =  62.7 MiB        python (6)
after.: 40.6 MiB +  10.3 MiB =  50.9 MiB        python (5)
-----
before: 11.4 MiB +  10.6 MiB =  22.0 MiB        Terminal <71a4d
after.: 11.2 MiB +  10.6 MiB =  21.8 MiB        Terminal <1d479
-----
before: 25.1 MiB +  11.0 MiB =  36.1 MiB        Browse <955b6c4
after.: 25.2 MiB +  11.0 MiB =  36.2 MiB        Browse <f54f896
-----
before: 16.6 MiB +  11.1 MiB =  27.7 MiB        Write <e0a3864e
after.: 17.3 MiB +  11.2 MiB =  28.5 MiB        Write <76c06ca2
-----
before: 11.1 MiB +  10.6 MiB =  21.6 MiB        Journal <38f01d
after.: 10.8 MiB +  10.5 MiB =  21.2 MiB        Journal <ff2f91
-----
before:  5.8 MiB +   1.7 MiB =   7.5 MiB        Xorg
after.: 16.9 MiB +   1.5 MiB =  18.4 MiB        Xorg

I hope I've done this right.  I used ps_mem.py (per tomeu) and a wrapper script to gather these
numbers[4].

Martin

PS -- things feel a lot faster.  2 MiB/activity (of which I can
generally get 4-5 usefully running at a time, and each of the ones
tested takes over 20 MiB of memory, so I'm not sacrificing one
potential activity I could be running) is fine by me - things feel a
good amount faster.

1. at least I think that's the change:
http://dev.laptop.org/~tomeu/matchbox-window-manager-1.2-3.20070628svn.fc7.i386.rpm

2. I could get Xorg to take up more memory by alt-tabbing as quickly
as possible (would get up to 22 MiB, from 18). It's really easy to do
this as alt-tabbing is now tons faster :).  I could get it back down
to 18.4 MiB by alt-tabbing through a few (at least 3, it seemed)
activities, but slowly.  Visiting any sugar shell screen(s)
didn't seem to have this effect.

3. Going from 7 to 18 MiB = 11 MiB / 4 activities (Journal, Terminal,
Write, and Browse) ~= 2.75 MiB / activity.  If you count the shell as
one activity (I think this makes sense if I understand what's going on
here), that's down to ~= 2.2 MiB / activity. After launching etoys
(which didn't seem to want to draw itself, but dunno if that's my
build or the compositing) and stopping it, Xorg was down to 16.1 MiB.
So I think there are some variables here I wasn't systematically
testing, but the ~2 MiB / activity guideline seems useful for
discussion.

4. The scripts and some raw outputs (I have much more, but I suppose
people that care may find it quicker to re-do my tests than page
through lots of my results) are:

http://www.xades.com/proj/xo-psmem-matchbox/before
http://www.xades.com/proj/xo-psmem-matchbox/after.
http://www.xades.com/proj/xo-psmem-matchbox/olpc-psmem
http://www.xades.com/proj/xo-psmem-matchbox/ps_mem.py
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