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Diffstat (limited to 'upstream/fedora-40/man5/iocost.conf.5')
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diff --git a/upstream/fedora-40/man5/iocost.conf.5 b/upstream/fedora-40/man5/iocost.conf.5 new file mode 100644 index 00000000..112f047f --- /dev/null +++ b/upstream/fedora-40/man5/iocost.conf.5 @@ -0,0 +1,96 @@ +'\" t +.TH "IOCOST\&.CONF" "5" "" "systemd 255" "iocost.conf" +.\" ----------------------------------------------------------------- +.\" * Define some portability stuff +.\" ----------------------------------------------------------------- +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.\" http://bugs.debian.org/507673 +.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.ie \n(.g .ds Aq \(aq +.el .ds Aq ' +.\" ----------------------------------------------------------------- +.\" * set default formatting +.\" ----------------------------------------------------------------- +.\" disable hyphenation +.nh +.\" disable justification (adjust text to left margin only) +.ad l +.\" ----------------------------------------------------------------- +.\" * MAIN CONTENT STARTS HERE * +.\" ----------------------------------------------------------------- +.SH "NAME" +iocost.conf \- Configuration files for the iocost solution manager +.SH "SYNOPSIS" +.PP +/etc/systemd/iocost\&.conf +/etc/systemd/iocost\&.conf\&.d/*\&.conf +.SH "DESCRIPTION" +.PP +This file configures the behavior of +"iocost", a tool mostly used by +\fBsystemd-udevd\fR(8) +rules to automatically apply I/O cost solutions to +/sys/fs/cgroup/io\&.cost\&.*\&. +.PP +The qos and model values are calculated based on benchmarks collected on the +\m[blue]\fBiocost\-benchmark\fR\m[]\&\s-2\u[1]\d\s+2 +project and turned into a set of solutions that go from most to least isolated\&. Isolation allows the system to remain responsive in face of high I/O load\&. Which solutions are available for a device can be queried from the udev metadata attached to it\&. By default the naive solution is used, which provides the most bandwidth\&. +.SH "CONFIGURATION DIRECTORIES AND PRECEDENCE" +.PP +The default configuration is set during compilation, so configuration is only needed when it is necessary to deviate from those defaults\&. The main configuration file is either in +/usr/lib/systemd/ +or +/etc/systemd/ +and contains commented out entries showing the defaults as a guide to the administrator\&. Local overrides can be created by creating drop\-ins, as described below\&. The main configuration file can also be edited for this purpose (or a copy in +/etc/ +if it\*(Aqs shipped in +/usr/) however using drop\-ins for local configuration is recommended over modifications to the main configuration file\&. +.PP +In addition to the "main" configuration file, drop\-in configuration snippets are read from +/usr/lib/systemd/*\&.conf\&.d/, +/usr/local/lib/systemd/*\&.conf\&.d/, and +/etc/systemd/*\&.conf\&.d/\&. Those drop\-ins have higher precedence and override the main configuration file\&. Files in the +*\&.conf\&.d/ +configuration subdirectories are sorted by their filename in lexicographic order, regardless of in which of the subdirectories they reside\&. When multiple files specify the same option, for options which accept just a single value, the entry in the file sorted last takes precedence, and for options which accept a list of values, entries are collected as they occur in the sorted files\&. +.PP +When packages need to customize the configuration, they can install drop\-ins under +/usr/\&. Files in +/etc/ +are reserved for the local administrator, who may use this logic to override the configuration files installed by vendor packages\&. Drop\-ins have to be used to override package drop\-ins, since the main configuration file has lower precedence\&. It is recommended to prefix all filenames in those subdirectories with a two\-digit number and a dash, to simplify the ordering of the files\&. This also defined a concept of drop\-in priority to allow distributions to ship drop\-ins within a specific range lower than the range used by users\&. This should lower the risk of package drop\-ins overriding accidentally drop\-ins defined by users\&. +.PP +To disable a configuration file supplied by the vendor, the recommended way is to place a symlink to +/dev/null +in the configuration directory in +/etc/, with the same filename as the vendor configuration file\&. +.SH "OPTIONS" +.PP +All options are configured in the [IOCost] section: +.PP +\fITargetSolution=\fR +.RS 4 +Chooses which I/O cost solution (identified by named string) should be used for the devices in this system\&. The known solutions can be queried from the udev metadata attached to the devices\&. If a device does not have the specified solution, the first one listed in +\fIIOCOST_SOLUTIONS\fR +is used instead\&. +.sp +E\&.g\&. +"TargetSolution=isolated\-bandwidth"\&. +.sp +Added in version 254\&. +.RE +.SH "SEE ALSO" +.PP +\fBudevadm\fR(8), +\m[blue]\fBThe iocost\-benchmarks github project\fR\m[]\&\s-2\u[1]\d\s+2, +\m[blue]\fBThe resctl\-bench documentation details how the values are obtained\fR\m[]\&\s-2\u[2]\d\s+2 +.SH "NOTES" +.IP " 1." 4 +iocost-benchmark +.RS 4 +\%https://github.com/iocost-benchmark/iocost-benchmarks +.RE +.IP " 2." 4 +The resctl-bench documentation details how the values are obtained +.RS 4 +\%https://github.com/facebookexperimental/resctl-demo/tree/main/resctl-bench/doc +.RE |