Before:

                 0 CPU-migrations           #    0.000 M/sec                    ( +-  -nan% )

After:

                 0 CPU-migrations           #    0.000 M/sec                    ( +-  0.00% )

Also factor out the noise printing function.
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/n/tip-z89h2v1bk1mikcbsf7e6v34q@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@elte.hu>