[yocto] Can anything be done about do_rootfs speed?

[Paul D. DeRocco]

I got really tired of waiting for builds on my lowly dual-core Atom
machine, so I went out and bought a nice fast machine with an i7-4770K and
a Samsung SSD. Full builds are now screechingly fast, over 10x compared to
the Atom.

But when making a tiny change, I still have to wait for do_rootfs. Since
this is a single task, it runs on a single core, so it only runs maybe
three times as fast. For my Gumstix stuff, it takes five minutes instead
of something like 15. That's a meaningful improvement, but it still seems
long when the task implementing the minor change took, oh, five seconds.
Since it's the one task that _always_ gets executed, it seems like a
bottleneck that should be addressed.

Is there any way, in the future, of breaking do_rootfs into multiple
threads, so they can take advantage of multiple cores? Or has something
like this been tried already, and found not to produce much of a speedup?
Or is the process intriniscally sequential?

-- 

Ciao,               Paul D. DeRocco
Paul                mailto:pderocco at ix.netcom.com