Lines Matching full:cpus
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
65 Omit Scheduling-Clock Ticks For Idle CPUs
78 scheduling-clock interrupts to idle CPUs, which is critically important
86 idle CPUs. That said, dyntick-idle mode is not free:
104 Omit Scheduling-Clock Ticks For CPUs With Only One Runnable Task
109 Note that omitting scheduling-clock ticks for CPUs with only one runnable
110 task implies also omitting them for idle CPUs.
113 sending scheduling-clock interrupts to CPUs with a single runnable task,
114 and such CPUs are said to be "adaptive-ticks CPUs". This is important
119 delayed during a given iteration, all the other CPUs will be forced to
121 by one less than the number of CPUs. In these situations, there is
125 boot parameter specifies the adaptive-ticks CPUs. For example,
126 "nohz_full=1,6-8" says that CPUs 1, 6, 7, and 8 are to be adaptive-ticks
127 CPUs. Note that you are prohibited from marking all of the CPUs as
128 adaptive-tick CPUs: At least one non-adaptive-tick CPU must remain
130 calls like gettimeofday() returns accurate values on adaptive-tick CPUs.
136 this means that your system must have at least two CPUs in order for
139 Finally, adaptive-ticks CPUs must have their RCU callbacks offloaded.
159 3. POSIX CPU timers prevent CPUs from entering adaptive-tick mode.
167 preventing CPUs with large numbers of perf events pending from
170 5. Scheduler statistics for adaptive-tick CPUs may be computed
171 slightly differently than those for non-adaptive-tick CPUs.
183 There are situations in which idle CPUs cannot be permitted to
188 using the CONFIG_RCU_NOCB_CPU=y Kconfig option. The specific CPUs to
190 which takes a comma-separated list of CPUs and CPU ranges, for example,
191 "1,3-5" selects CPUs 1, 3, 4, and 5. Note that CPUs specified by
194 The offloaded CPUs will never queue RCU callbacks, and therefore RCU
195 never prevents offloaded CPUs from entering either dyntick-idle mode
197 pin the "rcuo" kthreads to specific CPUs if desired. Otherwise, the
221 Note: this test requires that your system have at least two CPUs.
251 CPUs, which can significantly reduce maximum performance.
269 nevertheless sends scheduling-clock interrupts to CPUs having a
285 simply offloading RCU callbacks from all CPUs and pinning them
291 interrupts and tasks to particular CPUs.
304 * Unless all CPUs are idle, at least one CPU must keep the
308 * If there might potentially be some adaptive-ticks CPUs, there
310 going, even if all CPUs are otherwise idle.