1# SPDX-License-Identifier: GPL-2.0-only 2 3choice 4 prompt "Preemption Model" 5 default PREEMPT_NONE 6 7config PREEMPT_NONE 8 bool "No Forced Preemption (Server)" 9 help 10 This is the traditional Linux preemption model, geared towards 11 throughput. It will still provide good latencies most of the 12 time, but there are no guarantees and occasional longer delays 13 are possible. 14 15 Select this option if you are building a kernel for a server or 16 scientific/computation system, or if you want to maximize the 17 raw processing power of the kernel, irrespective of scheduling 18 latencies. 19 20config PREEMPT_VOLUNTARY 21 bool "Voluntary Kernel Preemption (Desktop)" 22 depends on !ARCH_NO_PREEMPT 23 help 24 This option reduces the latency of the kernel by adding more 25 "explicit preemption points" to the kernel code. These new 26 preemption points have been selected to reduce the maximum 27 latency of rescheduling, providing faster application reactions, 28 at the cost of slightly lower throughput. 29 30 This allows reaction to interactive events by allowing a 31 low priority process to voluntarily preempt itself even if it 32 is in kernel mode executing a system call. This allows 33 applications to run more 'smoothly' even when the system is 34 under load. 35 36 Select this if you are building a kernel for a desktop system. 37 38config PREEMPT 39 bool "Preemptible Kernel (Low-Latency Desktop)" 40 depends on !ARCH_NO_PREEMPT 41 select PREEMPT_COUNT 42 select UNINLINE_SPIN_UNLOCK if !ARCH_INLINE_SPIN_UNLOCK 43 help 44 This option reduces the latency of the kernel by making 45 all kernel code (that is not executing in a critical section) 46 preemptible. This allows reaction to interactive events by 47 permitting a low priority process to be preempted involuntarily 48 even if it is in kernel mode executing a system call and would 49 otherwise not be about to reach a natural preemption point. 50 This allows applications to run more 'smoothly' even when the 51 system is under load, at the cost of slightly lower throughput 52 and a slight runtime overhead to kernel code. 53 54 Select this if you are building a kernel for a desktop or 55 embedded system with latency requirements in the milliseconds 56 range. 57 58endchoice 59 60config PREEMPT_COUNT 61 bool 62