1 # SPDX-License-Identifier: GPL-2.0-only
3 config HAVE_PREEMPT_LAZY
7 def_bool y if HAVE_PREEMPT_LAZY && PREEMPT_RT
10 prompt "Preemption Model"
14 bool "No Forced Preemption (Server)"
16 This is the traditional Linux preemption model, geared towards
17 throughput. It will still provide good latencies most of the
18 time, but there are no guarantees and occasional longer delays
21 Select this option if you are building a kernel for a server or
22 scientific/computation system, or if you want to maximize the
23 raw processing power of the kernel, irrespective of scheduling
26 config PREEMPT_VOLUNTARY
27 bool "Voluntary Kernel Preemption (Desktop)"
28 depends on !ARCH_NO_PREEMPT
30 This option reduces the latency of the kernel by adding more
31 "explicit preemption points" to the kernel code. These new
32 preemption points have been selected to reduce the maximum
33 latency of rescheduling, providing faster application reactions,
34 at the cost of slightly lower throughput.
36 This allows reaction to interactive events by allowing a
37 low priority process to voluntarily preempt itself even if it
38 is in kernel mode executing a system call. This allows
39 applications to run more 'smoothly' even when the system is
42 Select this if you are building a kernel for a desktop system.
45 bool "Preemptible Kernel (Low-Latency Desktop)"
46 depends on !ARCH_NO_PREEMPT
48 select UNINLINE_SPIN_UNLOCK if !ARCH_INLINE_SPIN_UNLOCK
50 This option reduces the latency of the kernel by making
51 all kernel code (that is not executing in a critical section)
52 preemptible. This allows reaction to interactive events by
53 permitting a low priority process to be preempted involuntarily
54 even if it is in kernel mode executing a system call and would
55 otherwise not be about to reach a natural preemption point.
56 This allows applications to run more 'smoothly' even when the
57 system is under load, at the cost of slightly lower throughput
58 and a slight runtime overhead to kernel code.
60 Select this if you are building a kernel for a desktop or
61 embedded system with latency requirements in the milliseconds
65 bool "Fully Preemptible Kernel (Real-Time)"
66 depends on EXPERT && ARCH_SUPPORTS_RT
70 This option turns the kernel into a real-time kernel by replacing
71 various locking primitives (spinlocks, rwlocks, etc.) with
72 preemptible priority-inheritance aware variants, enforcing
73 interrupt threading and introducing mechanisms to break up long
74 non-preemptible sections. This makes the kernel, except for very
75 low level and critical code paths (entry code, scheduler, low
76 level interrupt handling) fully preemptible and brings most
77 execution contexts under scheduler control.
79 Select this if you are building a kernel for systems which
80 require real-time guarantees.