readme

rtai-3.1-test3的源代码(Real-Time Application Interface )

Latency Testing and Calibration
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This test is the counterpart of the latency calibration found in the kernel 
test suite and can be used just to monitor jitter in both periodic and oneshot
mode. In the latter case the figures displayed can be used also to calibrate 
the scheduling latency in oneshot mode.
Try it under load and see that it is not so bad, compared to its kernel brother.
For a quick idea of min/max jitters note that you should take away the average 
from min/max. The difference in averages between the latency calibration run 
for the kernel module and the one here gives you a fair idea of the overhead 
of doing it in user space. You'll see that what you get is just a bit more 
overhead, not really bad taking into account what must be done to run it in 
user space, but not much more jitter. 
Various execution mode are possible, please have a look at the related README
found in kern/latency for an explanation of the related setup parameters,
though you must note that they are in the form of macros here. So you have to
recompile before trying a new test configuration.
The only difference to be be noticed is that in user space the FPU support is 
always active, so the related parameter doesn not exist.