On Sat, 27 Oct 2007, Karel Kulhavy wrote: > I am raytraing a video with a command "rt" and the "top" is showing this: > > CPU states: 48.4% user, 48.7% nice, 3.0% system, 0.0% interrupt, 0.0% idle > [...] > PID USERNAME PRI NICE SIZE RES STATE WAIT TIME CPU COMMAND > 29174 clock 79 10 33M 15M run - 0:00 4.25% rt > > What is the "nice" state? I know what userspace, system, interrupt handler > and idle task is, but nice? > > CL<
man 1 nice. man 1 top. man 3 sysctl vide KERN_CPTIME The nice value is added to the basic priority of a task. The higher the "nice", the less likely a task is to get CPU time, so called because it is being "nice" to other users. It's part of an ancient unix work-around for not having proper prioritized batch queues and a more versatile scheduler. The standard joke is that there actually was a user who once voluntarily ran nice on a time-sharing system. Top's 48.7% nice here is telling you that the CPU is spending 48.7% of its time executing tasks that are "niced". If this includes processes with negative "nice" values, I do not know; you could peruse the kernel source or conduct an experiment to discover that, if you care to. Dave
