CPU加载均值

深入了解Linux CPU加载-你应该在什么时候担忧?
很可能非常熟悉Linux装载的平均值。加载的平均值
可以采用uptime和top指令，显示如下，例如：
14:08:12 up 9 min,  2 users,  load average: 0.31, 0.31, 0.16
很多人混淆了加载平均值的涵义：三个值代表在其中逐步增长的时间段
内CPU的负载情况。数字越小越好。
但是阀值是多少？什么是好的或者坏的负载平均值？什么时候你应该
担忧平均负载值，还有什么时候需要去抢救修复？
首先，了解加载平均值的背景是非常有意义的。我们从最简单的例子开始研究
：单处理器。

交通模拟
单核CPU即使一个单车道。

 

You might be familiar with Linux load averages already. Load averages are the
three numbers shown with the uptime and top commands - they look like this:
load average: 0.09, 0.05, 0.01
Most people have an inkling of what the load averages mean: the three numbers
represent averages over progressively longer periods of time (one, five, and fifteen
minute averages), and that lower numbers are better. Higher numbers represent
a problem or an overloaded machine. But, what's the the threshold? What constitutes
"good" and "bad" load average values? When should you be concerned over a load
average value, and when should you scramble to fix it ASAP?

First, a little background on what the load average values mean.
 We'll start out with the simplest case: a machine with one single-core processor.