Building RELENG_9 (or RELENG_9_*) on a small machine?

[Darren Pilgrim]

On 2013-03-01 10:50, Ian Smith wrote:
> At 256MB - the
> minimum earlier that completed installation without disabling CTL - swap
> often sat at ~14MB but blew out to around 165MB building those huge llvm
> libraries - cc1plus 332M, 173M resident was one top I snipped, but I
> can't say I caught the biggest.

I had top running throughout a build and saw cc1plus reach 460 MB with 
171MB resident, at that point CPU was down to about 4% and the system 
was hammering swap.  As a testament to FreeBSD's robustness, I could 
still log in via ssh, start screened shells, and generally conduct admin 
tasks while cc1plus beat the crap out of my VM.  Even start and stop 
other services.

> Then I added 128MB (to 384MB) and repeated the first buildworld (incl.
> clang) expecting huge savings as it'd only touched swap to about 12MB a
> time or two, mostly having 100MB+ of free memory .. wow, down to 7h02m!

For 9.x, I changed my notes to "256 MB to run, 768 MB to build".  For 
8.x, the numbers were 192 MB to run, 512 MB to build.

> Here at least, building llvm libs and clang doubles buildworld time! and
> extends /usr/obj from 675MB to 1GB.

I'll be doing `make buildkernel buildworld` ET and size comparisons 
between RELENG_8_3 and RELENG_9_1 when I test out my buildbox.  I'd like 
to gather memory usage metrics as well, if someone knows some tricks for 
that.  My current approach is somewhat crude. :)  If there's interest 
I'll follow up with the results here.