[cadynce] On being able to pace periodic application strings... (Comparing Linux 2.6.9 and 2.6.20-rt8)

[Gautam Thaker]

Hi Adam, Raytheon and James, (and others):

One thing you may want to be careful of is how you actual subject the 
application strings to the update rates that you want. If one looks at 
message arrival rates in:

https://escher.isis.vanderbilt.edu/twiki/pub/CADYNCE/OneFiftyFiftyCase1/WorkloadDescription.htm

one observes that there are some non well-rounded values for message 
rates. In any event, one wants to have good control over rate at which 
we inject messages into our experiments. In our tests ultimately we rely 
on 'nanosleep()' to accurately pace our message rates. (this or similar 
must be what CUTS based models use, James?) Please see the following 
link that shows if you use non-RT Linux kernel you may get some strange 
results. It is for this reason, among others, that  we test w/ RT Linux. 
PoR is also  using RT Linux.

http://www.atl.external.lmco.com/projects/QoS/RTOS_html/timer_gran/linux_2.6.9_and_2.6.20-rt8_compared.html

Gautam