Why perftest(ib_send_bw, ib_write_bw and so on) has a high CPU usage (100%)?

When running the basic perftest command like:

ib_write_bw -a ip.

I observe that in the cpu usage (use command top in Ubuntu) of the client is very high, like 100%. And from published papers, I think the CPU usage of IB is very low. Why is the cpu usage of ib_write_bw so high?


Use --cpu_util to see the exact cpu utilization.

If you use htop, refer the red color to see how much the kernel space has been used.

In my test I can see on the sender 4.17 % and on the receive side 0%.

I let you check.