cpu-usage - ksoftirq is NOT using CPU and should be, why?

Question

Both Linux 2.6 and 3.8. Linux setup as a router passing a 3 gig file

Doing a top, %SI is high at 30%, but ksoftirqd is doing 0% CPU. So the question is "What thread is handling the softirq???" I've read the code and it is suppose to be ksoftirqd, but it is idle.

[can't post image, not enough points]

Is this an accounting issue?

dreez

Answer 1

当负载不能用 %SI 处理时，它将被卸载到 softirqd。所以你会看到 %SI 30 和 %softirqd 0。

从手册页。ksoftirqd 是一个 per-cpu 内核线程，当机器处于重软中断负载下时运行。软中断通常在从硬中断返回时得到服务，但软中断的触发速度可能比它们被服务的速度更快。如果在处理软中断时第二次触发软中断，则会触发 ksoftirq 守护进程以处理进程上下文中的软中断。如果 ksoftirqd 占用的 CPU 时间超过很小的百分比，这表明机器处于沉重的软中断负载下。