thrash

thrash vi.  To move wildly or violently, without
   accomplishing anything useful.  Paging or swapping systems that are
   overloaded waste most of their time moving data into and out of
   core (rather than performing useful computation) and are therefore
   said to thrash.  Someone who keeps changing his mind (esp. about
   what to work on next) is said to be thrashing.  A person
   frantically trying to execute too many tasks at once (and not
   spending enough time on any single task) may also be described as
   thrashing.  Compare {multitask}.