| # Boot time |
| |
| Boot time is a measurement of the time elapsed since the system was last powered |
| on. It is set to zero whenever the kernel initializes the system's timer |
| hardware, which happens well before userspace is initialized. Boot time is |
| guaranteed to progress during periods of Suspend-To-Idle. |
| |
| Boot time is always available and guaranteed to be continuous and monotonic. It |
| ticks at a rate determined by the the underlying hardware oscillator, and no |
| attempts are made by Zircon to correct that rate against any external reference. |
| |
| Components may read boot time using [`zx_clock_get_boot`][clock-get-boot]. |
| |
| [clock-get-boot]: https://fuchsia.dev/reference/syscalls/clock_get_boot |
