Which statement about nice values on Linux is correct?
LPIC-1 Exam 101-500, objective 103. GNU and Unix commands medium
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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 short set from objective 103 and space the ones you get wrong.
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