1 2choice 3 prompt "Preemption Model" 4 default PREEMPT_NONE 5 6config 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 19config 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 36config 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 55endchoice 56 57config PREEMPT_COUNT 58 bool