When an x86 Linux system is powered up and running, how does it keep track of software time? E.g. is it incrementing a software counter based on hardware interrupts from the RTC, or is there some internal timer on the x86 chip, or something else entirely?
When I do a cat of /proc/interrupts, interrupt 8 (the RTC interrupt) has only fired once.
Also what could be causing the system time to be running faster on some systems, in a fleet of identical deployed hardware?