Root/
1 | |
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)" |
21 | help |
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, |
26 | at the cost of slightly lower throughput. |
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 |
32 | under load. |
33 | |
34 | Select this if you are building a kernel for a desktop system. |
35 | |
36 | config PREEMPT |
37 | bool "Preemptible Kernel (Low-Latency Desktop)" |
38 | select PREEMPT_COUNT |
39 | select UNINLINE_SPIN_UNLOCK if !ARCH_INLINE_SPIN_UNLOCK |
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 |
48 | system is under load, at the cost of slightly lower throughput |
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 |
56 | |
57 | config PREEMPT_COUNT |
58 | bool |
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
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v3.9