I've been planning to write a blog post about profiling D on
Linux for a while, and... while I still didn't get around to
writing an actual post, I recently gave a talk/workshop about
profiling/optimizing on Linux at local hackerspace.
While it's aimed at the local C/C++ audience, a lot of it is
relevant to D (especially perf, which works well with D - except
for name mangling - I keep hearing about people using
valgrind/callgrind with D but never got it to work myself).
Slides and sample code:
http://defenestrate.eu/2014/10/31/profiling_on_linux.html