`Moe` wrote:Well, I think even using just a text-mode program for PGO is better than none at all, since there's a lot in DOSBox that can be optimized and which is not graphics mode dependent.
Definitely agreed. Having written and optimized a couple of emulators myself, it is rare that the code base is breaking performance on a sub-system of the emulated machine, but more often the problems in performance are per-tick cycle costs that you pay regardless of code execution. Not always, but it would certainly benefit you to run a general simulation of a DOS program no matter how simple it is, so you can get the optimizer thinking about basic instruction scheduling costs and the like.
Of course, you can still build a pathologically bad set of code for a specific case (we had a couple of these in Atari800) but they are usually easily isolated and identified "hey, when I run in graphics mode 7, my frame rate drops 50%!".
-Frob