The diagram below shows task states in a 16-processor parallel
computer running an LU-factorization algorithm. White states indicate
that no tasks are active on the processor (as at the beginning) and
blue indicates that a task is waiting in a barrier (and so doing no
useful work). Utilization is the area of potions not blue or white
divided by the total area, less than one half. The text was rendered
for a higher-resolution device, and so is hard to read.
Also available in PostScript (246 kB PostScript).
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Arrival Rate
The graph below shows the rate of traffic entering a network (arrival
rate) in a 16-processor parallel computer running an LU-factorization
algorithm. The time scale approximately matches the graph above.
Note that the arrival rate depends upon the number of active
processors and on what those processors are doing. The y-axis is
labeled "Rate / ( Flits / 128 Cycles ) x 10, an admittedly awkward
measure of arrival rate. (A flit is the amount of data that can be
transfered in one cycle.) Also available in
PostScript (25.3 kB PostScript).
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