= Credit notes =

Some random notes about credit.

== Inconsistent goals ==

Consider these goals:

 * Project neutrality: a given host should get the same credit/day from any project.
 * Device neutrality: a given job should get the same credit on different hosts.

Consider the following scenario:

 * Two projects and two hosts
 * Host A runs both projects' jobs in 1 hour.
 * Host B runs project 1's jobs in 1 hour, and project 2's job in 10 hours.

Project neutrality says that both projects must grant host A the same credit per job.
Then device neutrality says that both projects must grant host B the same credit per job.
But that violates project neutrality for host B.

So the two goals are inconsistent; we can't satisfy them both.

== Scenarios ==

Extending the above example:
suppose
 * the 2 hosts both have the same peak FP speed (say 1 GFLOPS).
 * project 1's app runs with 100% efficiency on both hosts
 * project 2's app runs with 100% efficiency on host A
   and 10% efficiency on host B
   (say, because of its memory access pattern)