> (I maintain the Linux vDSO, and the HPET has so many problems that I disabled vDSO HPET support entirely a while back.) For those who don't know: the vDSO is

> (I maintain the Linux vDSO, and the HPET has so many problems that I disabled vDSO HPET support entirely a while back.) For those who don't know: the vDSO is a "dynamic library" provided by the Linux kernel to every process. System calls in modern Linux are made by calling a function exported by the vDSO, which then does the real system call, using the fastest method available. There are a few special cases in the vDSO for time-related system calls: depending on the currently active clock source, it can do a few calculations and return, without having to actually do a system call. This makes getting the current time much faster.