Lines Matching full:idle
19 2. Omit scheduling-clock ticks on idle CPUs (CONFIG_NO_HZ_IDLE=y or
23 3. Omit scheduling-clock ticks on CPUs that are either idle or that
40 that use short bursts of CPU, where there are very frequent idle
41 periods, but where these idle periods are also quite short (tens or
46 other than increasing the overhead of switching to and from idle and
52 However, if you are instead running a light workload with long idle
65 Omit Scheduling-Clock Ticks For Idle CPUs
68 If a CPU is idle, there is little point in sending it a scheduling-clock
71 and an idle CPU has no duties to shift its attention among.
73 An idle CPU that is not receiving scheduling-clock interrupts is said to
74 be "dyntick-idle", "in dyntick-idle mode", "in nohz mode", or "running
75 tickless". The remainder of this document will use "dyntick-idle mode".
78 scheduling-clock interrupts to idle CPUs, which is critically important
86 idle CPUs. That said, dyntick-idle mode is not free:
89 to and from the idle loop.
91 2. On many architectures, dyntick-idle mode also increases the
96 in order to avoid degrading from-idle transition latencies.
99 dyntick-idle mode in CONFIG_NO_HZ_IDLE=y kernels by specifying "nohz=off".
101 dyntick-idle mode.
110 task implies also omitting them for idle CPUs.
120 wait idle while the delayed CPU finishes. Thus, the delay is multiplied
147 Just as with dyntick-idle mode, the benefits of adaptive-tick mode do
151 adaptive ticks without also running dyntick idle. This dependency
183 There are situations in which idle CPUs cannot be permitted to
184 enter either dyntick-idle mode or adaptive-tick mode, the most
195 never prevents offloaded CPUs from entering either dyntick-idle mode
229 * Dyntick-idle slows transitions to and from idle slightly.
232 dyntick-idle mode, an option that most of them take. However,
240 b. On x86 systems, use the "idle=mwait" boot parameter.
245 d. On x86 systems, use the "idle=poll" boot parameter.
249 be even worse than that of dyntick-idle. Furthermore,
280 * A reboot is required to reconfigure both adaptive idle and RCU
304 * Unless all CPUs are idle, at least one CPU must keep the
310 going, even if all CPUs are otherwise idle.