Previous | Next --- Slide 3 of 36
Back to Lecture Thumbnails
Xelblade

In this demo, first we had one person sum up ~14 numbers, which took around 34 seconds. We then had two people far away from each other sum up half the numbers each, but only allowing communication through the passing of a sheet of paper. It took around 18 seconds for the partial sums to be computed, but a total of ~30 seconds for the final sum to be called out due to the "communication time" of passing the paper.

Even though we had double the "processors", the speedup was not 2 because of the overhead from communication.

pebbled

Some potential solutions to this issue were also discussed. We could attempt to reduce latency in communication of the "processors" by moving them closer together or improving their communication speed, analogous to positioning silicon and reducing memory latency IRL. Alternatively, this job could be performed serially, as the overhead of parallelism is not worthwhile for such small jobs.