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cc19ca86 | 1 | |
f8cbd99b IM |
2 | choice |
3 | prompt "Preemption Model" | |
4 | default PREEMPT_NONE | |
5 | ||
6 | config PREEMPT_NONE | |
7 | bool "No Forced Preemption (Server)" | |
8 | help | |
9 | This is the traditional Linux preemption model, geared towards | |
10 | throughput. It will still provide good latencies most of the | |
11 | time, but there are no guarantees and occasional longer delays | |
12 | are possible. | |
13 | ||
14 | Select this option if you are building a kernel for a server or | |
15 | scientific/computation system, or if you want to maximize the | |
16 | raw processing power of the kernel, irrespective of scheduling | |
17 | latencies. | |
18 | ||
19 | config PREEMPT_VOLUNTARY | |
20 | bool "Voluntary Kernel Preemption (Desktop)" | |
cc19ca86 | 21 | help |
f8cbd99b IM |
22 | This option reduces the latency of the kernel by adding more |
23 | "explicit preemption points" to the kernel code. These new | |
24 | preemption points have been selected to reduce the maximum | |
25 | latency of rescheduling, providing faster application reactions, | |
3dde6ad8 | 26 | at the cost of slightly lower throughput. |
f8cbd99b IM |
27 | |
28 | This allows reaction to interactive events by allowing a | |
29 | low priority process to voluntarily preempt itself even if it | |
30 | is in kernel mode executing a system call. This allows | |
31 | applications to run more 'smoothly' even when the system is | |
cc19ca86 IM |
32 | under load. |
33 | ||
f8cbd99b IM |
34 | Select this if you are building a kernel for a desktop system. |
35 | ||
36 | config PREEMPT | |
37 | bool "Preemptible Kernel (Low-Latency Desktop)" | |
bdd4e85d | 38 | select PREEMPT_COUNT |
e335e3eb | 39 | select UNINLINE_SPIN_UNLOCK if !ARCH_INLINE_SPIN_UNLOCK |
f8cbd99b IM |
40 | help |
41 | This option reduces the latency of the kernel by making | |
42 | all kernel code (that is not executing in a critical section) | |
43 | preemptible. This allows reaction to interactive events by | |
44 | permitting a low priority process to be preempted involuntarily | |
45 | even if it is in kernel mode executing a system call and would | |
46 | otherwise not be about to reach a natural preemption point. | |
47 | This allows applications to run more 'smoothly' even when the | |
3dde6ad8 | 48 | system is under load, at the cost of slightly lower throughput |
f8cbd99b IM |
49 | and a slight runtime overhead to kernel code. |
50 | ||
51 | Select this if you are building a kernel for a desktop or | |
52 | embedded system with latency requirements in the milliseconds | |
53 | range. | |
54 | ||
55 | endchoice | |
cc19ca86 | 56 | |
bdd4e85d FW |
57 | config PREEMPT_COUNT |
58 | bool |