Mastering Linux Kernel Development

High-precision event timer (HPET)

The HPET works with clock signals in excess of 10 Mhz, issuing interrupts once every 100 nano seconds, hence the name high-precision. HPET implements a 64-bit main counter to count at such a high frequency. It was co-developed by Intel and Microsoft for the need of a new high-resolution timer. HPET embeds a collection of timers. Each of them is capable of issuing interrupts independently, and can be used by specific applications as assigned by the kernel. These timers are managed as groups of timers, where each group can have a maximum of 32 timers in it. An HPET can implement maximum of 8 such groups. Each timer has a set of comparator and match register. A timer issues an interrupt when the value in its ...