blob: e35a11526feab69374a66f97985ae9e0ad5a76ee [file] [log] [blame]
if BLOCK
menu "IO Schedulers"
config IOSCHED_NOOP
bool
default y
---help---
The no-op I/O scheduler is a minimal scheduler that does basic merging
and sorting. Its main uses include non-disk based block devices like
memory devices, and specialised software or hardware environments
that do their own scheduling and require only minimal assistance from
the kernel.
config IOSCHED_TEST
tristate "Test I/O scheduler"
depends on DEBUG_FS
default m
---help---
The test I/O scheduler is a duplicate of the noop scheduler with
addition of test utlity.
It allows testing a block device by dispatching specific requests
according to the test case and declare PASS/FAIL according to the
requests completion error code.
config IOSCHED_DEADLINE
tristate "Deadline I/O scheduler"
default y
---help---
The deadline I/O scheduler is simple and compact. It will provide
CSCAN service with FIFO expiration of requests, switching to
a new point in the service tree and doing a batch of IO from there
in case of expiry.
config IOSCHED_ROW
tristate "ROW I/O scheduler"
default y
---help---
The ROW I/O scheduler gives priority to READ requests over the
WRITE requests when dispatching, without starving WRITE requests.
Requests are kept in priority queues. Dispatching is done in a RR
manner when the dispatch quantum for each queue is calculated
according to queue priority.
Most suitable for mobile devices.
config IOSCHED_CFQ
tristate "CFQ I/O scheduler"
default y
---help---
The CFQ I/O scheduler tries to distribute bandwidth equally
among all processes in the system. It should provide a fair
and low latency working environment, suitable for both desktop
and server systems.
This is the default I/O scheduler.
config CFQ_GROUP_IOSCHED
bool "CFQ Group Scheduling support"
depends on IOSCHED_CFQ && BLK_CGROUP
default n
---help---
Enable group IO scheduling in CFQ.
choice
prompt "Default I/O scheduler"
default DEFAULT_CFQ
help
Select the I/O scheduler which will be used by default for all
block devices.
config DEFAULT_DEADLINE
bool "Deadline" if IOSCHED_DEADLINE=y
config DEFAULT_ROW
bool "ROW" if IOSCHED_ROW=y
help
The ROW I/O scheduler gives priority to READ requests
over the WRITE requests when dispatching, without starving
WRITE requests. Requests are kept in priority queues.
Dispatching is done in a RR manner when the dispatch quantum
for each queue is defined according to queue priority.
Most suitable for mobile devices.
config DEFAULT_CFQ
bool "CFQ" if IOSCHED_CFQ=y
config DEFAULT_NOOP
bool "No-op"
endchoice
config DEFAULT_IOSCHED
string
default "deadline" if DEFAULT_DEADLINE
default "row" if DEFAULT_ROW
default "cfq" if DEFAULT_CFQ
default "noop" if DEFAULT_NOOP
endmenu
endif