Why the trigered counts of NMIs is equivalent to PMI's?

As the subject, here is the statics got from my PC at a different time: $cat /proc/interrupts | grep -E 'NMI|PMI' NMI: 649 374 347 424 Non-maskable interrupts PMI: 649 374 347 424 Performance monitoring interrupts $ cat /proc/interrupts | grep -Ei 'PMI|NMI' NMI: 247 274 238 289 Non-maskable interrupts PMI: 247 274 238 289 Performance monitoring interrupts