The aligment traps are unbelievably useful in user space if we put them
in. Yes it needs you to add a piece of code to the program (crtalign.o
anyone). But it can tell you what kind of badly aligned operations you
are doing, and give you a dump to study.
There are a couple of other profiling items that would be nice to have
visible via user space. Tracing both page faults and TLB misses.