Linux system load average command and the meaning of the three numbers

1. System Average Load - Basic Explanation

In the Linux shell, there are many commands to see the Load Average, such as:

[email protected]:~# uptime
12:49:10 up 182 days, 16:54, 2 users, load average: 0.08, 0.04, 0.01

[email protected]:~# w
12:49:18 up 182 days, 16:54, 2 users, load average: 0.11, 0.07, 0.01

[email protected]:~# top
top – 12:50:28 up 182 days, 16:55, 2 users, load average: 0.02, 0.05, 0.00

Let me first explain the meaning of these three numbers: they represent the average number of processes in the system's running process queue in the past 1 minute, 5 minutes, and 15 minutes respectively.

2. The impact of host performance

1. Single-core CPU – numbers between 0.00-1.00 are normal

Numbers between 0.00-1.00 indicate that the road conditions are very good, there is no congestion, and vehicles can pass without hindrance.

1.00 means the road is fair, but could deteriorate and cause congestion. At this point, the system has no extra resources and the administrator needs to optimize it.

1.00- * means the road condition is not very good. If it reaches 2.00, it means there are twice as many vehicles waiting as on the bridge. In this case you must get checked.

2. Multi-core CPU – The number/CPU core count is normal between 0.00-1.00

For multi-core CPUs, the full load figure is "1.00 * number of CPU cores", that is, 2.00 for a dual-core CPU and 4.00 for a quad-core CPU.

3. Safe system load average

A single-core load below 0.7 is safe, but if it exceeds 0.7, optimization is required.

4. Which number should I look at, 1 minute, 5 minutes or 15 minutes?

It is better to look at the 5-minute and 15-minute ones, that is, the last two numbers.

5. How do I know how many cores my CPU has?

Use the following command to directly obtain the number of CPU cores

grep 'model name' /proc/cpuinfo | wc -l

Conclusion

Get the number of CPU cores N, observe the last two numbers, and divide the number by N. If the value obtained is less than 0.7, there is no need to worry.

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