Module time 

Cheap monotonic clocks.

now_ns is the precise monotonic clock (CLOCK_MONOTONIC through the vDSO on Linux, QueryPerformanceCounter on Windows). coarse_ns is cheaper and has the resolution of the kernel tick: CLOCK_MONOTONIC_COARSE on Linux (same epoch as now_ns); elsewhere it is the precise clock. Both count nanoseconds from an arbitrary fixed point.

Functions

coarse_ns

Nanoseconds on the cheapest monotonic clock (kernel-tick resolution on Linux).

now_ns

Nanoseconds on the precise monotonic clock.

process_cpu_ns

CPU time (user and system) used by the whole process so far, in nanoseconds: CLOCK_PROCESS_CPUTIME_ID on Unix, GetProcessTimes on Windows (100 ns steps, updated at the scheduler tick). For measurements such as “an idle server uses no CPU”.

wall_ns

Nanoseconds since the Unix epoch on the wall clock (0 if it is set before 1970). On Linux a direct clock_gettime: SystemTime costs code for its error path.