CS475 Lab 7 Iso-efficiency
In this lab you will determine the iso-efficiency of summing n numbers
on a one dimensional grid of processors P1-P2-P3-...-Pp. This is a 1-D
version of the exercise done in Lecture QuinnChapter7, slides 26 and on.
It takes 1 time step to add two numbers, and 500 time steps to communicate
a message from Pi to Pi+1 , or Pi+1 to Pi, no matter how large the message.
- Determine T1 and Tp, in terms of n and p
- Determine Sp, in terms of n and p
- Determine Ep, in terms of n and p
- Make a table for Ep for rows n = 6000, n=36000, n=168000
and columns p=2, p=4, p=8
- What is the efficiency on the diagonal of the table?
- Express the iso-efficiency of adding n numbers on a 1D grd of
processors in terms of p.