
220 CHAPTER 4 Workload-Driven Evaluation
3.
Data layout, distribution, and alignment. Even if appropriate data structures are
used, they may not be distributed or aligned appropriately to pages or cache
blocks, causing excess local traffic or artifactual communication.
4.
Orchestrating of communication and synchronization. The resulting communi-
cation and synchronization may be structured in less than optimal ways—for
example, sending small instead of large messages in message passing.
While optimizations can often be ad hoc, these categories impose some structure.
Where appropriate, we should compare the robustness of machines or features