Chen, Kenneth W writes:
Update p->timestamp to "now" in activate_task() doesn't look right
to me at all. p->timestamp records last time it was running on a
cpu. activate_task shouldn't update that variable when it queues
a task on the runqueue.
This bug (and combined with others) triggers improper load balancing.
The updated timestamp was placed there by Ingo to detect on-runqueue time. If it is being used for load balancing then it is being used in error.