LXR linux/block/Kconfig.iosched

   1if BLOCK
   2
   3menu "IO Schedulers"
   4
   5config IOSCHED_NOOP
   6        bool
   7        default y
   8        ---help---
   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
  13          the kernel.
  14
  15config IOSCHED_AS
  16        tristate "Anticipatory I/O scheduler"
  17        default y
  18        ---help---
  19          The anticipatory I/O scheduler is generally a good choice for most
  20          environments, but is quite large and complex when compared to the
  21          deadline I/O scheduler, it can also be slower in some cases
  22          especially some database loads.
  23
  24config IOSCHED_DEADLINE
  25        tristate "Deadline I/O scheduler"
  26        default y
  27        ---help---
  28          The deadline I/O scheduler is simple and compact, and is often as
  29          good as the anticipatory I/O scheduler, and in some database
  30          workloads, better. In the case of a single process performing I/O to
  31          a disk at any one time, its behaviour is almost identical to the
  32          anticipatory I/O scheduler and so is a good choice.
  33
  34config IOSCHED_CFQ
  35        tristate "CFQ I/O scheduler"
  36        default y
  37        ---help---
  38          The CFQ I/O scheduler tries to distribute bandwidth equally
  39          among all processes in the system. It should provide a fair
  40          working environment, suitable for desktop systems.
  41          This is the default I/O scheduler.
  42
  43choice
  44        prompt "Default I/O scheduler"
  45        default DEFAULT_CFQ
  46        help
  47          Select the I/O scheduler which will be used by default for all
  48          block devices.
  49
  50        config DEFAULT_AS
  51                bool "Anticipatory" if IOSCHED_AS=y
  52
  53        config DEFAULT_DEADLINE
  54                bool "Deadline" if IOSCHED_DEADLINE=y
  55
  56        config DEFAULT_CFQ
  57                bool "CFQ" if IOSCHED_CFQ=y
  58
  59        config DEFAULT_NOOP
  60                bool "No-op"
  61
  62endchoice
  63
  64config DEFAULT_IOSCHED
  65        string
  66        default "anticipatory" if DEFAULT_AS
  67        default "deadline" if DEFAULT_DEADLINE
  68        default "cfq" if DEFAULT_CFQ
  69        default "noop" if DEFAULT_NOOP
  70
  71endmenu
  72
  73endif
  74