Answers are grounded in this paper and cite their sources.
While much current research concerns multiprocessor design, few traces of parallel programs are available for analyzing the effect of design trade-offs. Existing trace collection methods have serious drawbacks: trap-driven methods often slow down program execution by more than 1000 times, significantly perturbing program behavior; microcode modification is faster, but the technique is neither general nor portable.
No takes yet. Share an insight, caveat, or question.
Eggers et al. (1990) studied this question.