Well the issue is not new, anyhow, following a conversation with Orit ...
Since we want the migration to finish, I believe that the "migration speed"
parameter alone cannot do the job.
I suggest using two distinct parameters:
1. Migration speed - will be used to limit the network resources utilization
2. aggressionLevel - A number between 0.0 and 1.0, where low values imply
minimal interruption to the guest, and 1.0 mean that the guest will be
completely stalled.
In any case the migration will have to do its work and finish given any actual
migration-speed, so even low aggressionLevel values will sometimes imply that
the guest will be throttled substantially.
The algorithm:
The aggressionLevel should determine the targetGuest%CPU (how much CPU time we
want to allocate to the guest)