Lessons learned from source upgrade from FreeBSD i386 9.2 Stable to FreeBSD i386 10.0 Release.

[Warren Block]

On Thu, 23 Jan 2014, Kevin Oberman wrote:

> On Thu, Jan 23, 2014 at 7:47 AM, Thomas Hoffmann <trh411 at gmail.com> wrote:
>       On Thu, Jan 23, 2014 at 9:56 AM, Warren Block <wblock at wonkity.com> wrote:
>       >
>       >
>       > Using -DNOCLEAN with an existing /usr/obj can go even faster than ccache:
>       > less than two minutes for a buildworld on my frequently updated i5/SSD
>       > system, sometimes less than one minute.
> 
> 
> Can you elaborate on this, please? I always clear my /usr/obj before
> starting a buildworld, which takes 2 hours to run on my system. Are you
> saying if I do "make -DNOCLEAN buildworld" I do not have to clear /usr/obj
> first

Yes.  Removing /usr/obj is a faster way of doing 'make clean', mostly.

> AND my buildworld will run faster

Yes, because make will see that many/most files have already been built.

> (AND with no downside)?

Well... mostly.  :)

I noticed that after 10.0-RELEASE, uname on my system still said 
"PRERELEASE".  That code had not been rebuilt because make did not see 
it as needing a rebuild.  You can still delete /usr/obj and run a full 
buildworld from scratch every so often.

I should give credit to bdrewery@ for reminding me about -DNOCLEAN when 
I was whining about ccache not working on 10.0.  It turned out to be a 
better solution.