Documentation/timers/highres.rst

8 https://www.kernel.org/doc/ols/2006/ols2006v1-pages-333-346.pdf
11 http://www.cs.columbia.edu/~nahum/w6998/papers/ols2006-hrtimers-slides.pdf
23 - hrtimer base infrastructure
24 - timeofday and clock source management
25 - clock event management
26 - high resolution timer functionality
27 - dynamic ticks
31 ---------------------------
40        - time ordered enqueueing into a rb-tree
41        - independent of ticks (the processing is based on nanoseconds)
45 -------------------------------------
48 code out of the architecture-specific areas into a generic management
70 ----------------------
81 to touch all the architecture-specific implementations in order to provide new
95 structure with clock-specific property parameters and callback functions. The
98 includes the distinction of per-CPU and per-system global event devices.
100 System-level global event devices are used for the Linux periodic tick. Per-CPU
107       - system global periodic tick (jiffies update)
108       - cpu local update_process_times
109       - cpu local profiling
110       - cpu local next event interrupt (non periodic mode)
136 adding the dynamic tick specific calls to the idle routine (a total of 3 lines
137 added to the idle function and the Kconfig file)
143 -----------------------------------
169 decision is made per timer base and synchronized across per-cpu timer bases in
170 a support function. The design allows the system to utilize separate per-CPU
171 clock event devices for the per-CPU timer bases, but currently only one
172 reprogrammable clock event device per-CPU is utilized.
176 red-black tree to a separate double linked list and invokes the softirq
182 context is the avoidance of up to two context switches - from the interrupted
187 switched off. This disables the per system global periodic clock event device -
190 The periodic tick functionality is provided by an per-cpu hrtimer. The callback
209 -------------
215 - hrtimer_stop_sched_tick
216 - hrtimer_restart_sched_tick
217 - hrtimer_update_jiffies
219 hrtimer_stop_sched_tick() is called when a CPU goes into idle state. The code
222 reprograms the sched_tick to this future event, to allow longer idle sleeps
224 called when an interrupt happens during the idle period, which does not cause a
229 hrtimer_restart_sched_tick() is called when the CPU leaves the idle state before
234 in the idle period to make sure that jiffies are up to date and the interrupt