I almost put exactly that in a footnote, 'cept about RAM, instead of CPU usage. No OS that I know of exposes such an API, so it's highly theoretical.
As for truly contiguous metrics, hmm. How about current battery charge (in Wh)? Host uptime also seems technically continuous (albeit representable by a straight line). (Yes, we track this met; it makes reboots stand out in lieu of my metrics system not providing a vertical marker feature.) Clock drift?
(and I'm going to insert the footnote on this comment about something something Planck units.)
As for truly contiguous metrics, hmm. How about current battery charge (in Wh)? Host uptime also seems technically continuous (albeit representable by a straight line). (Yes, we track this met; it makes reboots stand out in lieu of my metrics system not providing a vertical marker feature.) Clock drift?
(and I'm going to insert the footnote on this comment about something something Planck units.)