[OE-core] Performance numbers

[Richard Purdie]

Its been a while since we had some performance numbers and there were
recently some questions about how current build time compared to
previous numbers.

On my 12 core system, build time for qemux86 from scratch is ~42
minutes. This compares favourably with previous numbers from that
system. Interestingly, switching to qemumips resulted in a build time of
43 minutes in the same tmpdir suggesting that the native part of the
bootstrap process isn't the bottleneck.

On the quad core (the system used for many of the previous numbers I'd
provided), build time for qemux86 was 105 minutes which again is roughly
consistent with where things were for 1.1.

So things haven't changed much recently which is as I'd expect. We
haven't seen many performance related patches but its good to know
things aren't regressing either.

Cheers,

Richard