projects / mirror_ubuntu-bionic-kernel.git / blame
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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)" | |
| 38 | help | |
| 39 | This option reduces the latency of the kernel by making | |
| 40 | all kernel code (that is not executing in a critical section) | |
| 41 | preemptible. This allows reaction to interactive events by | |
| 42 | permitting a low priority process to be preempted involuntarily | |
| 43 | even if it is in kernel mode executing a system call and would | |
| 44 | otherwise not be about to reach a natural preemption point. | |
| 45 | This allows applications to run more 'smoothly' even when the | |
| 3dde6ad8 | 46 | system is under load, at the cost of slightly lower throughput |
| f8cbd99b IM |
47 | and a slight runtime overhead to kernel code. |
| 48 | ||
| 49 | Select this if you are building a kernel for a desktop or | |
| 50 | embedded system with latency requirements in the milliseconds | |
| 51 | range. | |
| 52 | ||
| 53 | endchoice | |
| cc19ca86 | 54 |