Q: How can I profile my program to see where it spends most of its
run time?
A: DJGPP includes a profiling facility. To use it, compile and link
with -pg option, run your program as you usually would, then run a
program called gprof:
gprof myprog.exe
(change myprog.exe to whatever name your program is). This will
print an execution profile. You can now look at the profile and try to
optimize the functions which take a large proportion of the execution
time.
Gprof is further documented in the Binutils docs as part of the
GNU Binutils distribution.