The hardirqs[-bpfcc] tool displays the total time spent servicing hardirqs (hardware interrupts). The following screenshot shows us running the hardirqs-bpfcc tool. Here, you can see the total time that was spent servicing hardirqs every 1 second (first parameter) for 3 seconds (second parameter):
Figure 4.14 – hardirqs-bpfcc showing the time that was spent servicing hardirqs every 1 second for 3 seconds
The following screenshot shows us using the same tool to generate a histogram of hard IRQ time distribution (via the -d switch):
Figure 14.15 – hardirqs-bpfcc -d showing a histogram
Notice how the majority of the network hardirqs (iwlwifi, 48 of them) take just between 4 to 7 microseconds to complete, though a few (three of them) take between 16 and 31 usecs.
You can find more examples of how to use the hardirqs[-bpfcc] tool at https://github...
