Reducing the time for buildworld

[Matthew Dillon]

   I hesitate to ask how much memory was configured originally.

   Certain subsystems within the buildworld build eat a huge amount of
   memory.  In particular, the GCC build within the buildworld has some
   huge and complex files which eat a lot of memory while running and a
   -j3 would potentially run three of those cc's simultaniously.

   I remember doing buildworlds on very old machines... with 256M of ram
   or less, and they would always bog down compiling gcc.  Configuring a lot
   of swap and not using any make parallelism got the build through those
   files.

   In modern day machines have enough memory that it's easy to forget about
   build requirements, but we've seen people running VMs make the same
   mistake of configuring too little memory.  If you are going to be running
   buildworlds I woulds say 512M is about the minimum that can be configured.

   And you should always configure outsized swap space, like a gigabyte or
   so, on VMs with low amounts of configured ram just so it can slog though
   the memory intensive bits.

						-Matt