## Nice

February 7, 2018

Abstract

Simple tool for using a (conﬁgurable) nice level for all processes.

The nice level has a range of $-20$ to $19$. A higher number means less priority. Mostly, normal processes will get $0$ and only the superuser (root) can use negative values. Also only root can lower the nice level of a process, so if you nice your Cactus Run to 19, you cannot renice it later to an lower nice-level. The nice level of single processes can be controled by the system commands $nice$ and/or $renice$. In the case of Cactus and Lamd this is not possible at startup. Therefore this thorn will set the nice level of your processes at CCTK_PARAMCHECK (in the beginning of the calculation).