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ec8f24b7 | 1 | # SPDX-License-Identifier: GPL-2.0-only |
cc19ca86 | 2 | |
f8cbd99b IM |
3 | choice |
4 | prompt "Preemption Model" | |
5 | default PREEMPT_NONE | |
6 | ||
7 | config 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 | ||
20 | config PREEMPT_VOLUNTARY | |
21 | bool "Voluntary Kernel Preemption (Desktop)" | |
87a4c375 | 22 | depends on !ARCH_NO_PREEMPT |
cc19ca86 | 23 | help |
f8cbd99b IM |
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, | |
3dde6ad8 | 28 | at the cost of slightly lower throughput. |
f8cbd99b IM |
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 | |
cc19ca86 IM |
34 | under load. |
35 | ||
f8cbd99b IM |
36 | Select this if you are building a kernel for a desktop system. |
37 | ||
38 | config PREEMPT | |
39 | bool "Preemptible Kernel (Low-Latency Desktop)" | |
87a4c375 | 40 | depends on !ARCH_NO_PREEMPT |
bdd4e85d | 41 | select PREEMPT_COUNT |
e335e3eb | 42 | select UNINLINE_SPIN_UNLOCK if !ARCH_INLINE_SPIN_UNLOCK |
f8cbd99b IM |
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 | |
3dde6ad8 | 51 | system is under load, at the cost of slightly lower throughput |
f8cbd99b IM |
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 | ||
58 | endchoice | |
cc19ca86 | 59 | |
bdd4e85d | 60 | config PREEMPT_COUNT |
72367933 | 61 | bool |