| 1 | if BLOCK |
| 2 | |
| 3 | menu "IO Schedulers" |
| 4 | |
| 5 | config IOSCHED_NOOP |
| 6 | bool |
| 7 | default y |
| 8 | ---help--- |
| 9 | The no-op I/O scheduler is a minimal scheduler that does basic merging |
| 10 | and sorting. Its main uses include non-disk based block devices like |
| 11 | memory devices, and specialised software or hardware environments |
| 12 | that do their own scheduling and require only minimal assistance from |
| 13 | the kernel. |
| 14 | |
| 15 | config IOSCHED_AS |
| 16 | tristate "Anticipatory I/O scheduler" |
| 17 | default y |
| 18 | ---help--- |
| 19 | The anticipatory I/O scheduler is generally a good choice for most |
| 20 | environments, but is quite large and complex when compared to the |
| 21 | deadline I/O scheduler, it can also be slower in some cases |
| 22 | especially some database loads. |
| 23 | |
| 24 | config IOSCHED_DEADLINE |
| 25 | tristate "Deadline I/O scheduler" |
| 26 | default y |
| 27 | ---help--- |
| 28 | The deadline I/O scheduler is simple and compact, and is often as |
| 29 | good as the anticipatory I/O scheduler, and in some database |
| 30 | workloads, better. In the case of a single process performing I/O to |
| 31 | a disk at any one time, its behaviour is almost identical to the |
| 32 | anticipatory I/O scheduler and so is a good choice. |
| 33 | |
| 34 | config IOSCHED_CFQ |
| 35 | tristate "CFQ I/O scheduler" |
| 36 | default y |
| 37 | ---help--- |
| 38 | The CFQ I/O scheduler tries to distribute bandwidth equally |
| 39 | among all processes in the system. It should provide a fair |
| 40 | working environment, suitable for desktop systems. |
| 41 | This is the default I/O scheduler. |
| 42 | |
| 43 | choice |
| 44 | prompt "Default I/O scheduler" |
| 45 | default DEFAULT_CFQ |
| 46 | help |
| 47 | Select the I/O scheduler which will be used by default for all |
| 48 | block devices. |
| 49 | |
| 50 | config DEFAULT_AS |
| 51 | bool "Anticipatory" if IOSCHED_AS=y |
| 52 | |
| 53 | config DEFAULT_DEADLINE |
| 54 | bool "Deadline" if IOSCHED_DEADLINE=y |
| 55 | |
| 56 | config DEFAULT_CFQ |
| 57 | bool "CFQ" if IOSCHED_CFQ=y |
| 58 | |
| 59 | config DEFAULT_NOOP |
| 60 | bool "No-op" |
| 61 | |
| 62 | endchoice |
| 63 | |
| 64 | config DEFAULT_IOSCHED |
| 65 | string |
| 66 | default "anticipatory" if DEFAULT_AS |
| 67 | default "deadline" if DEFAULT_DEADLINE |
| 68 | default "cfq" if DEFAULT_CFQ |
| 69 | default "noop" if DEFAULT_NOOP |
| 70 | |
| 71 | endmenu |
| 72 | |
| 73 | endif |