1if BLOCK 2 3menu "IO Schedulers" 4 5config 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 15config 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 24config 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 34config 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 43choice 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 62endchoice 63 64config 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 71endmenu 72 73endif 74