Idleness Signal

[Eric Newhuis]

I have a "time trial" test whereby I cram a bunch of data into a 
multi-process single-node Erlang application and then wait for things to 
"settle down". 

The application has a lot of messaging and I do not wish to intrude on 
the messaging pipeline to determine an exact event-driven completion 
signal.  My goal is to determine the total cost of processing my batch 
of input messages and to compare the various run times among different 
algorithms, data structures, optimizations, etc.

I also intend to use eprof to investigate with finer granularity to help 
explain differences in "time trial" results.  So I am not seeking a 
substitute for eprof.  I love eprof.  I am building a complimentary tool.

Can anyone suggest alternatives for raising a signal that says that an 
Erlang node is idle?

I am currently entertaining the thought of polling the total REDS, as 
seen in erl's i() output and terminating my test when the REDS is 
unchanged for 1 second.  Since I think I am all CPU bound during this 
test I think this will work.  (I/O-bound conditions may effect false 
triggers.)

Is there a more clever way to raise such a signal?  ...more clever than 
polling REDS?  I don't need precision beyond 1 second; my time trial is 
expected to run for several minutes to an hour.

Sincerely,
Eric Newhuis