kvm_extirq

This time we want to analysis who triggers external irq the most. While current infrastructure doesn't support this, we need to add an event to track this.

Add an new event kvm_extirq

The patch file lists the changes necessary.

Analysis

Then the analysis is simple, execute following command:

perf record -e 'kvm:kvm_extirq2' -a sleep 30
perf report

The result looks like this:

# 78.01%  Ext irq2 0 - vec 253 causing vmexit
# 18.05%  Ext irq2 0 - vec 236 causing vmexit
#  2.22%  Ext irq2 124 - vec 33 causing vmexit
#  0.83%  Ext irq2 0 - vec 252 causing vmexit
#  0.69%  Ext irq2 0 - vec 251 causing vmexit
#  0.15%  Ext irq2 125 - vec 33 causing vmexit
#  0.05%  Ext irq2 123 - vec 33 causing vmexit