Linux-内核线程抢占

Question

I've got some realtime linux kernel and I'm developing some code with kernel thread. This thread is called by ethernet interrupt handler. I noticed that every call of this thread takes about 100 jiffies. In this time it reads about 256 ethernet frames. The ethernet is 1Gbps and download speed which I measured is about 4MB/s. I think that 4MB/s speed using 1Gbps ethernet is far too slow.

I'm trying to profile this kernel thread, because I think that 100 jiffies is too much. I'd like to ask if there is any way to tell how many times this kernel thread has been preempted?

Answer 1

If you are inside the thread, you can give a try with the following printk("preempt count is %d\\n",current_thread_info()->preempt_count);

You can add this at the entry of the thread and check the count difference between successive prints