Lecture 4

Learning objectives

After this class, you should be able to:

1. Explain the difference between SIMD and MIMD.
2. Describe the following interconnection networks: ring, toroidal mesh, hypercube, fat tree.
3. Given an interconnection network, determine its bisection bandwidth.
4. Give examples to explain the cache coherence and false sharing problems.
5. Explain the following terms: uniform memory access, non-uniform memory access, and false sharing.

Reading assignment

1. Lecture 4 slides.
2. Section 2.3.
3. Page 49.

Exercises and review questions

• Questions on current lecture's material
  1. (Post on the discussion board) Give a pseudocode that demonstrates false sharing.
  2. Give an example of an existing supercomputer that uses the fat tree interconnect topology.

• Questions on next lecture's material
  1. (Post on the discussion board) Give a pseudocode that demonstrates non-determinism.