134 lines
3.9 KiB
Plaintext
134 lines
3.9 KiB
Plaintext
if BLOCK
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menu "IO Schedulers"
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config IOSCHED_NOOP
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bool
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default y
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---help---
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The no-op I/O scheduler is a minimal scheduler that does basic merging
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and sorting. Its main uses include non-disk based block devices like
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memory devices, and specialised software or hardware environments
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that do their own scheduling and require only minimal assistance from
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the kernel.
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config IOSCHED_TEST
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tristate "Test I/O scheduler"
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depends on DEBUG_FS
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default m
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---help---
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The test I/O scheduler is a duplicate of the noop scheduler with
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addition of test utlity.
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It allows testing a block device by dispatching specific requests
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according to the test case and declare PASS/FAIL according to the
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requests completion error code.
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config IOSCHED_DEADLINE
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tristate "Deadline I/O scheduler"
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default y
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---help---
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The deadline I/O scheduler is simple and compact. It will provide
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CSCAN service with FIFO expiration of requests, switching to
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a new point in the service tree and doing a batch of IO from there
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in case of expiry.
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config IOSCHED_ROW
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tristate "ROW I/O scheduler"
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default y
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---help---
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The ROW I/O scheduler gives priority to READ requests over the
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WRITE requests when dispatching, without starving WRITE requests.
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Requests are kept in priority queues. Dispatching is done in a RR
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manner when the dispatch quantum for each queue is calculated
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according to queue priority.
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Most suitable for mobile devices.
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config IOSCHED_CFQ
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tristate "CFQ I/O scheduler"
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default y
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---help---
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The CFQ I/O scheduler tries to distribute bandwidth equally
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among all processes in the system. It should provide a fair
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and low latency working environment, suitable for both desktop
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and server systems.
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This is the default I/O scheduler.
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config CFQ_GROUP_IOSCHED
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bool "CFQ Group Scheduling support"
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depends on IOSCHED_CFQ && BLK_CGROUP
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default n
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---help---
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Enable group IO scheduling in CFQ.
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config IOSCHED_BFQ
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tristate "BFQ I/O scheduler"
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default n
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---help---
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The BFQ I/O scheduler tries to distribute bandwidth among
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all processes according to their weights.
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It aims at distributing the bandwidth as desired, independently of
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the disk parameters and with any workload. It also tries to
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guarantee low latency to interactive and soft real-time
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applications. If compiled built-in (saying Y here), BFQ can
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be configured to support hierarchical scheduling.
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config CGROUP_BFQIO
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bool "BFQ hierarchical scheduling support"
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depends on CGROUPS && IOSCHED_BFQ=y
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default n
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---help---
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Enable hierarchical scheduling in BFQ, using the cgroups
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filesystem interface. The name of the subsystem will be
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bfqio.
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choice
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prompt "Default I/O scheduler"
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default DEFAULT_CFQ
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help
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Select the I/O scheduler which will be used by default for all
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block devices.
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config DEFAULT_DEADLINE
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bool "Deadline" if IOSCHED_DEADLINE=y
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config DEFAULT_ROW
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bool "ROW" if IOSCHED_ROW=y
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help
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The ROW I/O scheduler gives priority to READ requests
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over the WRITE requests when dispatching, without starving
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WRITE requests. Requests are kept in priority queues.
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Dispatching is done in a RR manner when the dispatch quantum
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for each queue is defined according to queue priority.
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Most suitable for mobile devices.
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config DEFAULT_CFQ
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bool "CFQ" if IOSCHED_CFQ=y
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config DEFAULT_BFQ
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bool "BFQ" if IOSCHED_BFQ=y
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help
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Selects BFQ as the default I/O scheduler which will be
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used by default for all block devices.
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The BFQ I/O scheduler aims at distributing the bandwidth
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as desired, independently of the disk parameters and with
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any workload. It also tries to guarantee low latency to
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interactive and soft real-time applications.
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config DEFAULT_NOOP
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bool "No-op"
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endchoice
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config DEFAULT_IOSCHED
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string
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default "deadline" if DEFAULT_DEADLINE
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default "row" if DEFAULT_ROW
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default "cfq" if DEFAULT_CFQ
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default "bfq" if DEFAULT_BFQ
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default "noop" if DEFAULT_NOOP
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endmenu
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endif
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