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
19 A no-op scheduler that really does nothing.
22 tristate "Anticipatory I/O scheduler"
25 The anticipatory I/O scheduler is generally a good choice for most
26 environments, but is quite large and complex when compared to the
27 deadline I/O scheduler, it can also be slower in some cases
28 especially some database loads.
30 config IOSCHED_DEADLINE
31 tristate "Deadline I/O scheduler"
34 The deadline I/O scheduler is simple and compact, and is often as
35 good as the anticipatory I/O scheduler, and in some database
36 workloads, better. In the case of a single process performing I/O to
37 a disk at any one time, its behaviour is almost identical to the
38 anticipatory I/O scheduler and so is a good choice.
41 tristate "CFQ I/O scheduler"
44 The CFQ I/O scheduler tries to distribute bandwidth equally
45 among all processes in the system. It should provide a fair
46 working environment, suitable for desktop systems.
47 This is the default I/O scheduler.
50 tristate "BFQ I/O scheduler"
53 The BFQ I/O scheduler tries to distribute bandwidth among
54 all processes in the system, according to their weights,
55 giving deterministic guarantees on the service provided.
58 tristate "V(R) I/O scheduler"
61 Requests are chosen according to SSTF with a penalty of rev_penalty
62 for switching head direction.
65 prompt "Default I/O scheduler"
68 Select the I/O scheduler which will be used by default for all
72 bool "Anticipatory" if IOSCHED_AS=y
74 config DEFAULT_DEADLINE
75 bool "Deadline" if IOSCHED_DEADLINE=y
78 bool "CFQ" if IOSCHED_CFQ=y
81 bool "BFQ" if IOSCHED_BFQ=y
84 bool "V(R)" if IOSCHED_VR=y
93 config DEFAULT_IOSCHED
95 default "anticipatory" if DEFAULT_AS
96 default "deadline" if DEFAULT_DEADLINE
97 default "cfq" if DEFAULT_CFQ
98 default "bfq" if DEFAULT_BFQ
99 default "vr" if DEFAULT_VR
100 default "noop" if DEFAULT_NOOP
101 default "fifo" if DEFAULT_FIFO