benchmark ram consumption of nest post boot

[jrollins]

There were two ideas for this batted around:

• compare output of free between "stupid_simple" and "nested" initramfs's.
• compare output of free between normal nest and nest stuffed with additional large random file
• make nest with no rootfs.cgz, pull rootfs.cgz with tftp into separate staging tmpfs, unpack root into it's own tmpfs, unmount staging tmpfs, etc. compare free

[jrollins]

on proton, with nested:

debirf-minimal login: root
0 debirf-minimal:~# free
             total       used       free     shared    buffers     cached
Mem:        256792     148876     107916          0          0     134060
-/+ buffers/cache:      14816     241976
Swap:            0          0          0
0 debirf-minimal:~#