On Fri, 2008-01-25 at 17:54 +1100, Benjamin Herrenschmidt wrote:

Here, I do the test of running 4 times the repro-case provided by Michel
with nice 19 and a dd eating CPU with nice 0.

Without this option, I get the dd at 100% and the nice 19 shells down
below it with whatever is left of the CPUs.

With this option, dd gets about 50% of one CPU and the niced processes
still get most of the time.

FYI. This is a 4 way G5 (ppc64)

Ben.