October 2017
Intermediate to advanced
586 pages
14h 8m
English
Content preview from Linux Device Drivers Development
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High-resolution timers (HRTs)
Standard timers are less accurate and do not suit real-time applications. HRTs, introduced in kernel v2.6.16 (and enabled by the CONFIG_HIGH_RES_TIMERS option in the kernel configuration) have a resolution in microseconds (up to nanoseconds, depending on the platform), compared to milliseconds on standard timers. The standard timer depends on HZ (since they rely on jiffies), whereas the HRT implementation is based on ktime.
The kernel and hardware must support an HRT before being used on your system. In other words, there must be architecture-dependent code implemented to access your hardware HRTs.