Re: HEADS-UP: Enabling WITH_DEBUG_FILES by default

On Wed, Feb 11, 2015 at 09:23:01PM -0700, Ian Lepore wrote:
> On Thu, 2015-02-12 at 04:11 +0000, Glen Barber wrote:
> > On Wed, Feb 11, 2015 at 08:56:00PM -0700, Ian Lepore wrote:
> > > On Wed, 2015-02-11 at 22:21 -0500, Ed Maste wrote:
> > > > On 11 February 2015 at 21:39, Glen Barber <gjb_at_freebsd.org> wrote:
> > > > >
> > > > > Within the next 24 hours, I will merge the release-install-debug branch
> > > > > into head, which will enable building and installing stripped debugging
> > > > > files by default.
> > > > >
> > > > > In general, this should have no significant impact, but any fallout will
> > > > > be addressed as soon as possible after the merge.
> > > > >
> > > > > Those that do not want debugging files built/installed by default should
> > > > > add 'WITHOUT_DEBUG_FILES=1' to src.conf(5).  This will also be noted in
> > > > > UPDATING.
> > > > 
> > > > Note that the debug files do consume a reasonably large amount of disk
> > > > space in both the OBJDIR and in the installed location under
> > > > /usr/lib/debug. Users with limited disk space will probably want to
> > > > disable them.  As an example, the installed debug data on my laptop is
> > > > about 2GB.
> > > 
> > > Seriously?  2GB is bigger than the entire filesystem on many ARM boards
> > > that do useful work.  Not to mention how long it will take to write all
> > > that to an sdcard (it already takes a long time to installworld/kernel
> > > to an sdcard and it's only 400MB).
> > > 
> > > Just what are these files, and what use will the average user make of
> > > them?
> > > 
> > > What use will I make of them, that is going to justify that every one of
> > > my couple-dozen build sandboxes will now be 4gb larger (a copy in obj
> > > and a copy in the nfs root that things install to)?
> > > 
> > > How much time will this add to a build?
> > > 
> > > Yeah yeah, I can update a couple dozen src.conf files to eliminate them,
> > > and that's not the biggest hassle in the world (but it's also not
> > > nothing).  It seems like this is a heavy enough load that it needs to
> > > justify its existance.
> > > 
> > 
> > The major benefit is that all debugging data that we need to properly
> > debug application crashes in the base system will be available
> > out-of-box.
> > 
> > There is a trade-off here, in both directions.  For arm, for example,
> > the trade-off is that the default installed userland would grow, however
> > when there is a PR regarding an application crash, the tools to diagnose
> > the issue are there by default (we do not need to ask that the utility
> > is rebuilt with debugging options enabled, and then recreate the crash).
> > 
> > I considered making this an opt-in thing for arm, but given the above
> > rationale, thought it would be more beneficial for the opposite route.
> > If you feel necessary, however, we can turn this off by default for now
> > for arm.
> > 
> > Glen
> > 
> 
> I can't imagine that anybody is going to be happy with an installed
> system size increase from 520 to 2520 MB no matter how much it helps
> debugging, especially considering the the typical installation media is
> in the 2-8 GB range (with lots of 2 and 4 GB cards out there because
> that's what vendors bundle with the boards).
> 

Absolutely understood.  As mentioned in a recent reply (before seeing
this email), I'll provide a closer estimate of what to expect soon.
Again, if you want this turned off for arm, that's fine.  I would,
however, like to see it enabled by default across the board eventually
(even for -RELEASE builds).

Glen