LFCS Essential Commands Practice Question
Exhibit
Refer to the exhibit. $ top -bn1 | head -5 top - 14:23:45 up 10 days, 2:15, 1 user, load average: 1.5, 2.0, 2.5 Tasks: 123 total, 1 running, 122 sleeping, 0 stopped, 0 zombie %Cpu(s): 25.0 us, 10.0 sy, 0.0 ni, 65.0 id, 0.0 wa, 0.0 hi, 0.0 si MiB Mem : 1984.4 total, 500.0 free, 1000.0 used, 484.4 buff/cache MiB Swap: 2048.0 total, 2048.0 free, 0.0 used. 1484.4 avail Mem
Based on the exhibit, what is the average CPU idle percentage over the last 15 minutes?
⚠ Common exam trap
Linux Foundation often tests the ability to correctly identify the 'idle' column in the 'average' row of 'mpstat' output, as candidates may mistakenly pick a value from a per-CPU row or confuse 'idle' with other columns like 'sys' or 'iowait'.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
65.0%
The average CPU idle percentage over the last 15 minutes is calculated from the 'idle' value in the 'average' row of the 'mpstat' output. In the exhibit, the 'average' row shows an 'idle' value of 65.0, meaning the CPU was idle 65.0% of the time on average across all CPUs over the 15-minute interval. Therefore, the correct answer is 65.0%.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
65.0%
Why this is correct
The %Cpu(s) line shows 65.0 id (idle).
- ✗
2.0
Why it's wrong here
That is the 5-minute load average.
- ✗
1.5
Why it's wrong here
That is the 1-minute load average.
- ✗
2.5
Why it's wrong here
That is the 15-minute load average.
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