Say Y here if you want to help to debug reduced OS jitter.
Say N here if you are unsure.
-choice
- prompt "Build-forced no-CBs CPUs"
- default RCU_NOCB_CPU_NONE
- depends on RCU_NOCB_CPU
- help
- This option allows no-CBs CPUs (whose RCU callbacks are invoked
- from kthreads rather than from softirq context) to be specified
- at build time. Additional no-CBs CPUs may be specified by
- the rcu_nocbs= boot parameter.
-
-config RCU_NOCB_CPU_NONE
- bool "No build_forced no-CBs CPUs"
- help
- This option does not force any of the CPUs to be no-CBs CPUs.
- Only CPUs designated by the rcu_nocbs= boot parameter will be
- no-CBs CPUs, whose RCU callbacks will be invoked by per-CPU
- kthreads whose names begin with "rcuo". All other CPUs will
- invoke their own RCU callbacks in softirq context.
-
- Select this option if you want to choose no-CBs CPUs at
- boot time, for example, to allow testing of different no-CBs
- configurations without having to rebuild the kernel each time.
-
-config RCU_NOCB_CPU_ZERO
- bool "CPU 0 is a build_forced no-CBs CPU"
- help
- This option forces CPU 0 to be a no-CBs CPU, so that its RCU
- callbacks are invoked by a per-CPU kthread whose name begins
- with "rcuo". Additional CPUs may be designated as no-CBs
- CPUs using the rcu_nocbs= boot parameter will be no-CBs CPUs.
- All other CPUs will invoke their own RCU callbacks in softirq
- context.
-
- Select this if CPU 0 needs to be a no-CBs CPU for real-time
- or energy-efficiency reasons, but the real reason it exists
- is to ensure that randconfig testing covers mixed systems.
-
-config RCU_NOCB_CPU_ALL
- bool "All CPUs are build_forced no-CBs CPUs"
- help
- This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs=
- boot parameter will be ignored. All CPUs' RCU callbacks will
- be executed in the context of per-CPU rcuo kthreads created for
- this purpose. Assuming that the kthreads whose names start with
- "rcuo" are bound to "housekeeping" CPUs, this reduces OS jitter
- on the remaining CPUs, but might decrease memory locality during
- RCU-callback invocation, thus potentially degrading throughput.
-
- Select this if all CPUs need to be no-CBs CPUs for real-time
- or energy-efficiency reasons.
-
-endchoice
-
endmenu # "RCU Subsystem"
config BUILD_BIN2C