CommitDebug trace events are useful for measuring, in detail, the time spent in
the various parts of a single transaction. Like all log events, they have a time
associated with them. This time comes for now(), which in a real fdb system is
only updated in the run loop. This renders the timestamps inaccurate in certain
CPU bound sections which don't have a wait, e.g. in the resolver.
We want to preserve the current behavior in simulation, where the timestamps are
artificial, deterministic between runs, and only updated in the run loop.
In a real system, we prefer to use a real clock so we can use the difference
between two trace events in the logs as a measurement of elapsed time.
This does not modify the behavior of other parts of the system, which use the
cached now() for various purposes.
Dan Adkins