[certi-dev] Question about NextEventRequest Service

[Roth, Christoph]

Hi,

 

I have got a question concerning synchronization. My scenario is the following:

 

I have two federates f1 and f2. Both are event based and use the NextEventRequest (NERQ) Service to advance time. The simulation loop in both federates looks like this:

 

...

rtiAmb->updateAttributeValues();

 

rtiAmb->nextEventRequest(newTime);

while(isAdvancing) {

                rtiAmb->tick2();

}

…

 

Both federates have a lookahead of 10. Assume both federates are at the same time (=0). Now, if both federates request for the same new time with very high value like newTime=1000000 the tick2()-call lasts very long (several seconds) until the simulation proceeds. Have you any idea about the reason for this long delay? It seems as if the delay depends on the low lookahead, because if I increase the lookahead up to the newTime value simulation is much faster.

 

In my opinion the low lookahead should have no influence on execution speed since both federates guarantee to not send any message with a lower timestamp than newTime+lookahead, so the simulation should be able to directly advance (This is what I could read in the IEEE 1516.1.2000 standard page139), or did I make a misstake?

 

My setup:

-          Ubuntu linux

-          Local execution

-          Certi 3.4.0

 

 

Thank you very much and regards,

Christoph