view block/Kconfig.iosched @ 595:92247f7e5d8a

pvSCSI: add sanity checks

Signed-off-by: Tomonari Horikoshi <t.horikoshi@jp.fujitsu.com>
Signed-off-by: Jun Kamada <kama@jp.fujitsu.com>
author Keir Fraser <keir.fraser@citrix.com>
date Tue Jul 08 09:29:42 2008 +0100 (2008-07-08)
parents 831230e53067
line source
2 menu "IO Schedulers"
5 bool
6 default y
7 ---help---
8 The no-op I/O scheduler is a minimal scheduler that does basic merging
9 and sorting. Its main uses include non-disk based block devices like
10 memory devices, and specialised software or hardware environments
11 that do their own scheduling and require only minimal assistance from
12 the kernel.
14 config IOSCHED_AS
15 tristate "Anticipatory I/O scheduler"
16 default y
17 ---help---
18 The anticipatory I/O scheduler is the default disk scheduler. It is
19 generally a good choice for most environments, but is quite large and
20 complex when compared to the deadline I/O scheduler, it can also be
21 slower in some cases especially some database loads.
24 tristate "Deadline I/O scheduler"
25 default y
26 ---help---
27 The deadline I/O scheduler is simple and compact, and is often as
28 good as the anticipatory I/O scheduler, and in some database
29 workloads, better. In the case of a single process performing I/O to
30 a disk at any one time, its behaviour is almost identical to the
31 anticipatory I/O scheduler and so is a good choice.
33 config IOSCHED_CFQ
34 tristate "CFQ I/O scheduler"
35 default y
36 ---help---
37 The CFQ I/O scheduler tries to distribute bandwidth equally
38 among all processes in the system. It should provide a fair
39 working environment, suitable for desktop systems.
41 choice
42 prompt "Default I/O scheduler"
43 default DEFAULT_CFQ
44 help
45 Select the I/O scheduler which will be used by default for all
46 block devices.
48 config DEFAULT_AS
49 bool "Anticipatory" if IOSCHED_AS=y
52 bool "Deadline" if IOSCHED_DEADLINE=y
54 config DEFAULT_CFQ
55 bool "CFQ" if IOSCHED_CFQ=y
57 config DEFAULT_NOOP
58 bool "No-op"
60 endchoice
63 string
64 default "anticipatory" if DEFAULT_AS
65 default "deadline" if DEFAULT_DEADLINE
66 default "cfq" if DEFAULT_CFQ
67 default "noop" if DEFAULT_NOOP
69 endmenu