To Thrash

1. To beat mercilessly.
2. To defeat utterly.
3. To thresh.
4. To move about wildly or violently; to flail; to labour.
5. (software) To extensively test a software system, giving a program various inputs and observing the behavior and outputs that result.
6. (computing) In computer architecture, to cause poor performance of a virtual memory (or paging) system.