ioschedset

Commandline tools to query and/or set the I/O schedulers for block devices on Linux systems.

The Tools

Querying Current I/O Schedulers

The provided io-get-sched tool will query the current I/O scheduler assigned to each block device.

Running with no args will print out a list of all block devices and their scheduler.

For example:

[user@hostname ~]$ io-get-sched 
sda:	bfq
sdb:	deadline
sr0:	bfq

You can also specify one or more block device names and it will only list those specifically.

For example:

[user@hostname ~]$ io-get-sched sdb
sdb:	deadline

Modifying A Block Device's I/O Scheduler

The provided io-set-sched tool will assign a given I/O scheduler to all or specific block devices.

It requires at least 1 argument: the I/O scheduler name.

You can get a list of available schedulers by running with --list.

For example:

[user@hostname ~]$ io-set-sched --list
mq-deadline kyber bfq none

So in this instance, the system has "mq-deadline" (deadline), "kyber", "bfq", and "none" (no-op) available.

While querying the current I/O scheduler for block devices or available schedulers does not require root, actually changing the I/O scheduler used for a block device does require root.

So io-set-sched will attempt to sudo as root before adjusting the I/O scheduler on block devices.

You can set the I/O scheduler for all devices by just providing the desired scheduler name as argument:

[user@hostname ~]$ io-set-sched kyber
Must be root to set IO Scheduler. Rerunning under sudo...

+ Successfully set sda to 'kyber'!
+ Successfully set sdb to 'kyber'!
+ Successfully set sr0 to 'kyber'!

To change individual / specific devices, pass their names as arguments following the scheduler name:

[user@hostname ~]$ io-set-sched kyber sda sr0
Must be root to set IO Scheduler. Rerunning under sudo...

+ Successfully set sda to 'kyber'!
+ Successfully set sr0 to 'kyber'!

Installation

Installation instructions follow below.

Manual Install

This distribution comes with a script, "install.sh" which takes into consideration the environment variables PREFIX and DESTDIR.

You can also specify these as arguments, for example:

./install.sh DESTDIR="${pkgdir}"

is treated the same as:

DESTDIR="${pkgdir}" ./install.sh

See `./install.sh --help' for more info.

Unless you are building a package or have special constraints, you can just run ./install.sh to install into the system globally, or ./install.sh PREFIX=$HOME to install into the local user's HOME directory.

The tools are written in bash and have no external dependencies.

Arch Linux

For installation under Arch Linux, there are two options.

The first option is the 'official' releases, which are available via AUR: https://aur.archlinux.org/packages/ioschedset

The second alternative option is suitable for local installs - the git project contains a PKGBUILD file which works from the git directory rather than from a source tarball.

From AUR (official package)

1. Download and extract the tarball from https://aur.archlinux.org/cgit/aur.git/snapshot/ioschedset.tar.gz

2. cd into 'ioschedset' directory

3. Run `makepkg' as your normal user (non-root)

4. Install the package:

   pacman -U ioschedset-.pkg.tar.

From local PKGBUILD

1. Either download a release from https://github.com/kata198/ioschedset/releases or use git to clone https://github.com/kata198/ioschedset . If you use git, there are tags for each official release which matches the version number (git tag -l to list tags, git branch -l to list branches). "master" should always match the latest official release.

2. Navigate into the 'ioschedset' directory

3. Run `makepkg' as your normal user (non-root)

4. Install the package:

   pacman -U ioschedset-.pkg.tar.