| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 1 | config PREEMPT |
| 2 | bool |
| 3 | select PREEMPT_COUNT |
| 4 | |
| 5 | config PREEMPT_RT_BASE |
| 6 | bool |
| 7 | select PREEMPT |
| 8 | |
| 9 | choice |
| 10 | prompt "Preemption Model" |
| 11 | default PREEMPT_NONE |
| 12 | |
| 13 | config PREEMPT_NONE |
| 14 | bool "No Forced Preemption (Server)" |
| 15 | help |
| 16 | This is the traditional Linux preemption model, geared towards |
| 17 | throughput. It will still provide good latencies most of the |
| 18 | time, but there are no guarantees and occasional longer delays |
| 19 | are possible. |
| 20 | |
| 21 | Select this option if you are building a kernel for a server or |
| 22 | scientific/computation system, or if you want to maximize the |
| 23 | raw processing power of the kernel, irrespective of scheduling |
| 24 | latencies. |
| 25 | |
| 26 | config PREEMPT_VOLUNTARY |
| 27 | bool "Voluntary Kernel Preemption (Desktop)" |
| 28 | help |
| 29 | This option reduces the latency of the kernel by adding more |
| 30 | "explicit preemption points" to the kernel code. These new |
| 31 | preemption points have been selected to reduce the maximum |
| 32 | latency of rescheduling, providing faster application reactions, |
| 33 | at the cost of slightly lower throughput. |
| 34 | |
| 35 | This allows reaction to interactive events by allowing a |
| 36 | low priority process to voluntarily preempt itself even if it |
| 37 | is in kernel mode executing a system call. This allows |
| 38 | applications to run more 'smoothly' even when the system is |
| 39 | under load. |
| 40 | |
| 41 | Select this if you are building a kernel for a desktop system. |
| 42 | |
| 43 | config PREEMPT__LL |
| 44 | bool "Preemptible Kernel (Low-Latency Desktop)" |
| 45 | select PREEMPT |
| 46 | select UNINLINE_SPIN_UNLOCK if !ARCH_INLINE_SPIN_UNLOCK |
| 47 | help |
| 48 | This option reduces the latency of the kernel by making |
| 49 | all kernel code (that is not executing in a critical section) |
| 50 | preemptible. This allows reaction to interactive events by |
| 51 | permitting a low priority process to be preempted involuntarily |
| 52 | even if it is in kernel mode executing a system call and would |
| 53 | otherwise not be about to reach a natural preemption point. |
| 54 | This allows applications to run more 'smoothly' even when the |
| 55 | system is under load, at the cost of slightly lower throughput |
| 56 | and a slight runtime overhead to kernel code. |
| 57 | |
| 58 | Select this if you are building a kernel for a desktop or |
| 59 | embedded system with latency requirements in the milliseconds |
| 60 | range. |
| 61 | |
| 62 | config PREEMPT_RTB |
| 63 | bool "Preemptible Kernel (Basic RT)" |
| 64 | select PREEMPT_RT_BASE |
| 65 | help |
| 66 | This option is basically the same as (Low-Latency Desktop) but |
| 67 | enables changes which are preliminary for the full preemptiple |
| 68 | RT kernel. |
| 69 | |
| 70 | config PREEMPT_RT_FULL |
| 71 | bool "Fully Preemptible Kernel (RT)" |
| 72 | depends on IRQ_FORCED_THREADING |
| 73 | select PREEMPT_RT_BASE |
| 74 | help |
| 75 | All and everything |
| 76 | |
| 77 | endchoice |
| 78 | |
| 79 | config PREEMPT_COUNT |
| 80 | bool |