Thanks, those are definitely good options.
I felt a little iffy about GDB's, especially since it's not cycle accurate.
Oh, yes. I should've mentioned that I did find Renesas' simulator. I immediately started looking for a possible Linux version and forgot about Renesas' own tool.
I guess that's the most straight forward way... to time it. I remember I was using the SCU timers and multiplying it by the duration of a scanline to get a rough estimate. That was pretty bad.