charts: introduce a scheduling "adherence" row

This draws the new scheduling "adherence" metric in a row below the top
IOWait/Idle% row.

The headings have moved down one to cover "adherence" instead,
which I think should help make the important IOWait/Idle% row
more visible as well as improving headings readability.

The adherence row should generally be either black or red, rarely
cyan.

Red indicates %age of sampling interval behind schedule for the
given sample, Cyan indicates same but ahead of schedule which
should be unusual/almost never happen.  Infact I think the
current sharing of the "close enough" epsilon as adherence
truncating threshold the ahead of schedule "close enough"
situations will always get truncated to zero.  So it might be
impossible to see any cyan adherence as-is right now.

A future commit will move the '\/\/\ # %name @ Hz' heading up to
the IOWait/Idle% putting it back in the upper right corner, but
only that one.

0 files changed, 0 insertions, 0 deletions