Which statement about nice values on Linux is correct?
LPIC-1 Exam 101-500, objective 103. GNU and Unix commands medium
Draft — not checked yet. This question was written from the published exam objectives and cites the clause it comes from, but nobody has yet read it against that clause and signed for it.
It is kept out of search results and out of mock exams until they have. Read the source below before you take the answer as settled.
The options
Not correct Nice values range from -19 to 20, and 0 is reserved for root-owned processes.
Wrong on both counts. The range is -20 to 19, and 0 is simply the default nice value inherited by ordinary processes.
Not correct Nice values range from -20 to 19, and a higher value means a higher scheduling priority.
Wrong direction. The range is right but the meaning is inverted — nice 19 is the lowest priority, not the highest.
Not correct Nice values range from 0 to 99, where 99 is the most favourable.
Wrong. 1-99 is the real-time priority range used by scheduling policies such as SCHED_FIFO, set with chrt, not the nice range.
Correct Nice values range from -20 to 19, and a higher value means a lower scheduling priority.
Correct. The name is the mnemonic: a process that is 'nicer' to others gets less CPU. -20 is the most favourable value, 19 the least.
Why
Nice runs from -20 (most favourable to the process) through 0 (the default) to 19 (least favourable). The counterintuitive part is the direction: raising the nice number lowers the priority.
Where this comes from
- Cited
- LPI exam objective 103.6
- What it says
- Know the nice value range and how it maps to scheduling priority.
Practise this
Reading one question is not practice. The trainer will draw a set from objective 103 and space the ones you get wrong.