Follow up on Default Desktop Experinece for 11.04

Kees Cook kees at
Wed Apr 13 18:39:20 UTC 2011

On Wed, Apr 13, 2011 at 06:26:39PM +0100, Matt Zimmerman wrote:
> On Wed, Apr 13, 2011 at 06:09:52PM +0100, Matt Zimmerman wrote:
> > On Tue, Apr 12, 2011 at 09:24:59AM -0700, Rick Spencer wrote:
> > > I followed up on the @ubuntu-desktop list to let people know that 11.04
> > > was still slated to default to Unity, and to give people a chance to
> > > escalate concerns. I cc’ed the @ubuntu-devel list as well for
> > > completeness. I do not believe any escalations have occurred or that the
> > > Desktop team has changed it's plan to default to Unity.
> > 
> > For the benefit of the tech board and readers of this list, here are the
> > archive links for those discussions:
> > 
> >
> >

Has the moderation queue been checked for more replies?

> I scanned over this, looking for the comments on quality.  In a TB capacity,
> I'm not that interested in the debates over this or that design decision, or
> how the original decision was made, so much as the central question of "is
> it ready to ship?"
> [...]

My specific email contains what I would classify as 3 types of issues:
- design
- crashes
- UI behavior anomalies

I will ignore "design" here.

The bulk of the UI behavior anomalies were induced by my use of
focus-follows-mouse. I was told that FFM is "not supported" by
Unity. After disabling FFM mid-friday the behavior anomalies went away.
(Should there be some kind of warning about ffm if it is detected?)

After updating to the latest-at-the-time (compiz 1:0.9.4+bzr20110407-0ubuntu2,
unity 3.8.4-0ubuntu1) on Friday night, I have seen no more crashes
(though I have not attempted to crash it using the widely-known 685552
bug). I do not know if it is related to disabling FFM or the massive
amount of bug fixes that went in. Possibly both.

Across the weekend while using Unity, compiz leaked memory like crazy. I
noticed when it hit the 4GB mark. I updated to the latest of everything on
Monday morning (compiz 1:0.9.4+bzr20110411-0ubuntu1, unity 3.8.6-0ubuntu1),
and totally rebooted to start from a clean slate. I ran valgrind against
compiz for 5 minutes and came away with thousands of small memory leaks
seen (I filed bug #758248).

The leaks seem better in the above version, though perhaps this is due
to changes in nux, seeing it shows up in the valgrind backtraces), as
after running the same session since Monday, compiz has not changed its
memory footprint hardly at all (hovers around 48M).

So, in summary... if we ignore the design issues, I would say a lot
of crashers have been fixed, potentially a lot of leaks fixed, and
that's great. I'm unclear how to measure what remains, but it seems that
focus-follows-mouse with auto-raise triggers a lot of problems (at least
for me). If it came to a vote right right now to switch back to Classic,
I would probably abstain. It doesn't feel clearly "ready" to me, but at
the same time, it shows enough promise that I'm equally uncomfortable
saying it should be pulled.


Kees Cook
Ubuntu Security Team

More information about the technical-board mailing list