1 # SPDX-License-Identifier: GPL-2.0-only
2
3 config PREEMPT_NONE_BUILD
4 bool
5
6 config PREEMPT_VOLUNTARY_BUILD
7 bool
8
9 config PREEMPT_BUILD
10 bool
11 select PREEMPTION
12 select UNINLINE_SPIN_UNLOCK if !ARCH_I
13
14 choice
15 prompt "Preemption Model"
16 default PREEMPT_NONE
17
18 config PREEMPT_NONE
19 bool "No Forced Preemption (Server)"
20 select PREEMPT_NONE_BUILD if !PREEMPT_
21 help
22 This is the traditional Linux preemp
23 throughput. It will still provide go
24 time, but there are no guarantees an
25 are possible.
26
27 Select this option if you are buildi
28 scientific/computation system, or if
29 raw processing power of the kernel,
30 latencies.
31
32 config PREEMPT_VOLUNTARY
33 bool "Voluntary Kernel Preemption (Des
34 depends on !ARCH_NO_PREEMPT
35 select PREEMPT_VOLUNTARY_BUILD if !PRE
36 help
37 This option reduces the latency of t
38 "explicit preemption points" to the
39 preemption points have been selected
40 latency of rescheduling, providing f
41 at the cost of slightly lower throug
42
43 This allows reaction to interactive
44 low priority process to voluntarily
45 is in kernel mode executing a system
46 applications to run more 'smoothly'
47 under load.
48
49 Select this if you are building a ke
50
51 config PREEMPT
52 bool "Preemptible Kernel (Low-Latency
53 depends on !ARCH_NO_PREEMPT
54 select PREEMPT_BUILD
55 help
56 This option reduces the latency of t
57 all kernel code (that is not executi
58 preemptible. This allows reaction t
59 permitting a low priority process to
60 even if it is in kernel mode executi
61 otherwise not be about to reach a na
62 This allows applications to run more
63 system is under load, at the cost of
64 and a slight runtime overhead to ker
65
66 Select this if you are building a ke
67 embedded system with latency require
68 range.
69
70 config PREEMPT_RT
71 bool "Fully Preemptible Kernel (Real-T
72 depends on EXPERT && ARCH_SUPPORTS_RT
73 select PREEMPTION
74 help
75 This option turns the kernel into a
76 various locking primitives (spinlock
77 preemptible priority-inheritance awa
78 interrupt threading and introducing
79 non-preemptible sections. This makes
80 low level and critical code paths (e
81 level interrupt handling) fully pree
82 execution contexts under scheduler c
83
84 Select this if you are building a ke
85 require real-time guarantees.
86
87 endchoice
88
89 config PREEMPT_COUNT
90 bool
91
92 config PREEMPTION
93 bool
94 select PREEMPT_COUNT
95
96 config PREEMPT_DYNAMIC
97 bool "Preemption behaviour defined on
98 depends on HAVE_PREEMPT_DYNAMIC && !PR
99 select JUMP_LABEL if HAVE_PREEMPT_DYNA
100 select PREEMPT_BUILD
101 default y if HAVE_PREEMPT_DYNAMIC_CALL
102 help
103 This option allows to define the pre
104 command line parameter and thus over
105 model defined during compile time.
106
107 The feature is primarily interesting
108 provide a pre-built kernel binary to
109 flavors they offer while still offer
110
111 The runtime overhead is negligible w
112 but if runtime patching is not avail
113 then the potential overhead should b
114
115 Interesting if you want the same pre
116 both Server and Desktop workloads.
117
118 config SCHED_CORE
119 bool "Core Scheduling for SMT"
120 depends on SCHED_SMT
121 help
122 This option permits Core Scheduling,
123 selection across SMT siblings. When
124 prctl(PR_SCHED_CORE) -- task selecti
125 will execute a task from the same 'c
126 matching task is found.
127
128 Use of this feature includes:
129 - mitigation of some (not all) SMT
130 - limiting SMT interference to impr
131
132 SCHED_CORE is default disabled. When
133 which is the likely usage by Linux d
134 be no measurable impact on performan
135
136 config SCHED_CLASS_EXT
137 bool "Extensible Scheduling Class"
138 depends on BPF_SYSCALL && BPF_JIT && D
139 select STACKTRACE if STACKTRACE_SUPPOR
140 help
141 This option enables a new scheduler
142 allows scheduling policies to be imp
143 achieve the following:
144
145 - Ease of experimentation and explor
146 iteration of new scheduling polici
147 - Customization: Building applicatio
148 implement policies that are not ap
149 schedulers.
150 - Rapid scheduler deployments: Non-d
151 scheduling policies in production
152
153 sched_ext leverages BPF struct_ops f
154 which exports function callbacks and
155 wish to implement scheduling policie
156 exported by sched_ext is struct sche
157 similar to struct sched_class.
158
159 For more information:
160 Documentation/scheduler/sched-ext.
161 https://github.com/sched-ext/scx
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