| choice | |
| prompt "Preemption Model" | |
| default PREEMPT_NONE | |
| config PREEMPT_NONE | |
| bool "No Forced Preemption (Server)" | |
| help | |
| This is the traditional Linux preemption model, geared towards | |
| throughput. It will still provide good latencies most of the | |
| time, but there are no guarantees and occasional longer delays | |
| are possible. | |
| Select this option if you are building a kernel for a server or | |
| scientific/computation system, or if you want to maximize the | |
| raw processing power of the kernel, irrespective of scheduling | |
| latencies. | |
| config PREEMPT_VOLUNTARY | |
| bool "Voluntary Kernel Preemption (Desktop)" | |
| help | |
| This option reduces the latency of the kernel by adding more | |
| "explicit preemption points" to the kernel code. These new | |
| preemption points have been selected to reduce the maximum | |
| latency of rescheduling, providing faster application reactions, | |
| at the cost of slightly lower throughput. | |
| This allows reaction to interactive events by allowing a | |
| low priority process to voluntarily preempt itself even if it | |
| is in kernel mode executing a system call. This allows | |
| applications to run more 'smoothly' even when the system is | |
| under load. | |
| Select this if you are building a kernel for a desktop system. | |
| config PREEMPT | |
| bool "Preemptible Kernel (Low-Latency Desktop)" | |
| help | |
| This option reduces the latency of the kernel by making | |
| all kernel code (that is not executing in a critical section) | |
| preemptible. This allows reaction to interactive events by | |
| permitting a low priority process to be preempted involuntarily | |
| even if it is in kernel mode executing a system call and would | |
| otherwise not be about to reach a natural preemption point. | |
| This allows applications to run more 'smoothly' even when the | |
| system is under load, at the cost of slightly lower throughput | |
| and a slight runtime overhead to kernel code. | |
| Select this if you are building a kernel for a desktop or | |
| embedded system with latency requirements in the milliseconds | |
| range. | |
| endchoice | |