Interviewers often ask about the key criterions which are used to characterize different RTL and HLS designs if your are on an HLS interview.
The computing time is particularly important metric for design quality. For RTL design, when describing synchronous circuits, one often uses the number of clock cycles to finish tasks as a measure of performance. However, for HLS design, it might not be appropriate to use clock rates since the clock frequency is specified as an input constraint to the synthesis tool and it’s feasible to generate different architectures for the same exact code by simply changing the target frequency. So, we need to use consumed time (seconds) for finishing the task.