auditing CPU usage

Today I got a question out of left field that made me think of the good old days when we used to rent computing time on the main frame per processor cycle. Management would like to have a break-down of used processor cycles (they really said that) per business unit.

I don't think the database can do that. There is cpu time in ASH, but that's only a sample per second, and it's ephemeral. Hardly useful for charge-back. The AWR copy of ASH is even worse - only part of ASH gets flushed to the AWR. There is no guarantee that the captured part even gives a representative picture of what each individual session used.. There used to be OS auditing tools for this purpose, but they cannot audit individual user sessions within the database, I guess.

Has anyone had this put to them? What did you come up with?

Cheers,
Tony

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