Kconfig.preempt 2.3 KB

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  1. choice
  2. prompt "Preemption Model"
  3. default PREEMPT_NONE
  4. config PREEMPT_NONE
  5. bool "No Forced Preemption (Server)"
  6. help
  7. This is the traditional Linux preemption model, geared towards
  8. throughput. It will still provide good latencies most of the
  9. time, but there are no guarantees and occasional longer delays
  10. are possible.
  11. Select this option if you are building a kernel for a server or
  12. scientific/computation system, or if you want to maximize the
  13. raw processing power of the kernel, irrespective of scheduling
  14. latencies.
  15. config PREEMPT_VOLUNTARY
  16. bool "Voluntary Kernel Preemption (Desktop)"
  17. help
  18. This option reduces the latency of the kernel by adding more
  19. "explicit preemption points" to the kernel code. These new
  20. preemption points have been selected to reduce the maximum
  21. latency of rescheduling, providing faster application reactions,
  22. at the cost of slighly lower throughput.
  23. This allows reaction to interactive events by allowing a
  24. low priority process to voluntarily preempt itself even if it
  25. is in kernel mode executing a system call. This allows
  26. applications to run more 'smoothly' even when the system is
  27. under load.
  28. Select this if you are building a kernel for a desktop system.
  29. config PREEMPT
  30. bool "Preemptible Kernel (Low-Latency Desktop)"
  31. help
  32. This option reduces the latency of the kernel by making
  33. all kernel code (that is not executing in a critical section)
  34. preemptible. This allows reaction to interactive events by
  35. permitting a low priority process to be preempted involuntarily
  36. even if it is in kernel mode executing a system call and would
  37. otherwise not be about to reach a natural preemption point.
  38. This allows applications to run more 'smoothly' even when the
  39. system is under load, at the cost of slighly lower throughput
  40. and a slight runtime overhead to kernel code.
  41. Select this if you are building a kernel for a desktop or
  42. embedded system with latency requirements in the milliseconds
  43. range.
  44. endchoice
  45. config PREEMPT_BKL
  46. bool "Preempt The Big Kernel Lock"
  47. depends on SMP || PREEMPT
  48. default y
  49. help
  50. This option reduces the latency of the kernel by making the
  51. big kernel lock preemptible.
  52. Say Y here if you are building a kernel for a desktop system.
  53. Say N if you are unsure.