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Via Cycle Timing (a.k.a. fixed work) |
Last Modified: 24 May 2001
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Notes after initial post: None.
The purpose and use of this test is quite similar to CPU
Overhead II's fixed time method and so many details are not restated
here. The main difference is that the timing code has been rewritten
so that it measures how much time it takes to do a fixed amount of work
rather than timing how much work could be done in a fixed amount of time.
Here are the results.
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RESULTS
Data is available. As can be seen, expected values of percent user time closely approximate that actually measured. This data represents the following cost to the user per interrupt in
nanoseconds:
The expected values are calculated using the above average cost and merely represent how well the actual values collectively represent a constant cost per interrupt. The calculation is basically subtracting the average cost from the time between two interrupts and then dividing the result by the time between two interrupts; this corresponds to the time between interrupts that did not go to handling the interrupt. The above statistical values correlate well with the corresponding values
from the fixed time method of
CPU Overhead II. Therefor, the fixed work method produces results
that are at least on a par with the fixed timing method.
NEW CODE
The Makefile
provides the usual target files including the executable "FixedWorker."
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