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_DEADLINE 16 tristate "Deadline I/O scheduler" 17 default y 18 ---help--- 19 The deadline I/O scheduler is simple and compact. It will provide 20 CSCAN service with FIFO expiration of requests, switching to 21 a new point in the service tree and doing a batch of IO from there 22 in case of expiry. 23 24config IOSCHED_CFQ 25 tristate "CFQ I/O scheduler" 26 select BLK_CGROUP if CFQ_GROUP_IOSCHED 27 default y 28 ---help--- 29 The CFQ I/O scheduler tries to distribute bandwidth equally 30 among all processes in the system. It should provide a fair 31 and low latency working environment, suitable for both desktop 32 and server systems. 33 34 This is the default I/O scheduler. 35 36config CFQ_GROUP_IOSCHED 37 bool "CFQ Group Scheduling support" 38 depends on IOSCHED_CFQ && CGROUPS 39 default n 40 ---help--- 41 Enable group IO scheduling in CFQ. 42 43config DEBUG_CFQ_IOSCHED 44 bool "Debug CFQ Scheduling" 45 depends on CFQ_GROUP_IOSCHED 46 select DEBUG_BLK_CGROUP 47 default n 48 ---help--- 49 Enable CFQ IO scheduling debugging in CFQ. Currently it makes 50 blktrace output more verbose. 51 52choice 53 prompt "Default I/O scheduler" 54 default DEFAULT_CFQ 55 help 56 Select the I/O scheduler which will be used by default for all 57 block devices. 58 59 config DEFAULT_DEADLINE 60 bool "Deadline" if IOSCHED_DEADLINE=y 61 62 config DEFAULT_CFQ 63 bool "CFQ" if IOSCHED_CFQ=y 64 65 config DEFAULT_NOOP 66 bool "No-op" 67 68endchoice 69 70config DEFAULT_IOSCHED 71 string 72 default "deadline" if DEFAULT_DEADLINE 73 default "cfq" if DEFAULT_CFQ 74 default "noop" if DEFAULT_NOOP 75 76endmenu 77 78endif 79