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
15 config IOSCHED_DEADLINE
16 tristate "Deadline I/O scheduler"
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
25 tristate "CFQ I/O scheduler"
26 # If BLK_CGROUP is a module, CFQ has to be built as module.
27 depends on (BLK_CGROUP=m && m) || !BLK_CGROUP || BLK_CGROUP=y
30 The CFQ I/O scheduler tries to distribute bandwidth equally
31 among all processes in the system. It should provide a fair
32 and low latency working environment, suitable for both desktop
35 This is the default I/O scheduler.
37 Note: If BLK_CGROUP=m, then CFQ can be built only as module.
39 config CFQ_GROUP_IOSCHED
40 bool "CFQ Group Scheduling support"
41 depends on IOSCHED_CFQ && BLK_CGROUP
44 Enable group IO scheduling in CFQ.
47 tristate "BFQ I/O scheduler"
48 depends on EXPERIMENTAL
51 The BFQ I/O scheduler tries to distribute bandwidth among
52 all processes according to their weights.
53 It aims at distributing the bandwidth as desired, independently of
54 the disk parameters and with any workload. It also tries to
55 guarantee low latency to interactive and soft real-time
56 applications. If compiled built-in (saying Y here), BFQ can
57 be configured to support hierarchical scheduling.
60 bool "BFQ hierarchical scheduling support"
61 depends on CGROUPS && IOSCHED_BFQ=y
64 Enable hierarchical scheduling in BFQ, using the cgroups
65 filesystem interface. The name of the subsystem will be
69 prompt "Default I/O scheduler"
72 Select the I/O scheduler which will be used by default for all
75 config DEFAULT_DEADLINE
76 bool "Deadline" if IOSCHED_DEADLINE=y
79 bool "CFQ" if IOSCHED_CFQ=y
82 bool "BFQ" if IOSCHED_BFQ=y
89 config DEFAULT_IOSCHED
91 default "deadline" if DEFAULT_DEADLINE
92 default "cfq" if DEFAULT_CFQ
93 default "bfq" if DEFAULT_BFQ
94 default "noop" if DEFAULT_NOOP