Provided by: irqbalance_1.3.0-0.1ubuntu0.18.04.1_amd64 
NAME
irqbalance - distribute hardware interrupts across processors on a multiprocessor system
SYNOPSIS
irqbalance
DESCRIPTION
The purpose of irqbalance is to distribute hardware interrupts across processors on a multiprocessor
system in order to increase performance.
OPTIONS
-o, --oneshot
Causes irqbalance to be run once, after which the daemon exits.
-d, --debug
Causes irqbalance to print extra debug information. Implies --foreground.
-f, --foreground
Causes irqbalance to run in the foreground (without --debug).
-j, --journal
Enables log output optimized for systemd-journal.
-p, --powerthresh=<threshold>
Set the threshold at which we attempt to move a CPU into powersave mode If more than <threshold>
CPUs are more than 1 standard deviation below the average CPU softirq workload, and no CPUs are
more than 1 standard deviation above (and have more than 1 IRQ assigned to them), attempt to place
1 CPU in powersave mode. In powersave mode, a CPU will not have any IRQs balanced to it, in an
effort to prevent that CPU from waking up without need.
-i, --banirq=<irqnum>
Add the specified IRQ to the set of banned IRQs. irqbalance will not affect the affinity of any
IRQs on the banned list, allowing them to be specified manually. This option is addative and can
be specified multiple times. For example to ban IRQs 43 and 44 from balancing, use the following
command line: irqbalance --banirq=43 --banirq=44
--deepestcache=<integer>
This allows a user to specify the cache level at which irqbalance partitions cache domains.
Specifying a deeper cache may allow a greater degree of flexibility for irqbalance to assign IRQ
affinity to achieve greater performance increases, but setting a cache depth too large on some
systems (specifically where all CPUs on a system share the deepest cache level), will cause
irqbalance to see balancing as unnecessary. irqbalance --deepestcache=2
The default value for deepestcache is 2.
-l, --policyscript=<script>
When specified, the referenced script will execute once for each discovered IRQ, with the sysfs
device path and IRQ number passed as arguments. Note that the device path argument will point to
the parent directory from which the IRQ attributes directory may be directly opened. The script
may specify zero or more key=value pairs that will guide irqbalance in the management of that IRQ.
Key=value pairs are printed by the script on stdout and will be captured and interpreted by
irqbalance. Irqbalance expects a zero exit code from the provided utility. Recognized key=value
pairs are:
ban=[true | false]
Directs irqbalance to exclude the passed in IRQ from balancing.
balance_level=[none | package | cache | core]
This allows a user to override the balance level of a given IRQ. By default the balance level is
determined automatically based on the pci device class of the device that owns the IRQ.
numa_node=<integer>
This allows a user to override the NUMA node that sysfs indicates a given device IRQ is local to.
Often, systems will not specify this information in ACPI, and as a result devices are considered
equidistant from all NUMA nodes in a system. This option allows for that hardware provided
information to be overridden, so that irqbalance can bias IRQ affinity for these devices toward
its most local node. Note that specifying a -1 here forces irqbalance to consider an interrupt
from a device to be equidistant from all nodes.
-s, --pid=<file>
Have irqbalance write its process id to the specified file. By default no pidfile is written.
The written pidfile is automatically unlinked when irqbalance exits. It is ignored when used with
--debug or --foreground.
-t, --interval=<time>
Set the measurement time for irqbalance. irqbalance will sleep for <time> seconds between samples
of the irq load on the system cpus. Defaults to 10.
ENVIRONMENT VARIABLES
IRQBALANCE_ONESHOT
Same as --oneshot.
IRQBALANCE_DEBUG
Same as --debug.
IRQBALANCE_BANNED_CPUS
Provides a mask of CPUs which irqbalance should ignore and never assign interrupts to.
SIGNALS
SIGHUP Forces a rescan of the available IRQs and system topology.
API
irqbalance is able to communicate via socket and return it's current assignment tree and setup, as well
as set new settings based on sent values. Socket is abstract, with a name in form of irqbalance<PID>.sock
, where <PID> is the process ID of irqbalance instance to communicate with. Possible values to send:
stats Retrieve assignment tree of IRQs to CPUs, in recursive manner. For each CPU node in tree, it's
type, number, load and whether the save mode is active are sent. For each assigned IRQ type, it's
number, load, number of IRQs since last rebalancing and it's class are sent. Refer to types.h file
for explanation of defines.
setup Get the current value of sleep interval, mask of banned CPUs and and list of banned IRQs.
settings sleep <s>
Set new value of sleep interval, <s> >= 1.
settings cpus <cpu_number1> <cpu_number2> ...
Ban listed CPUs from IRQ handling, all old values of banned CPUs are forgotten.
settings ban irqs <irq1> <irq2> ...
Ban listed IRQs from being balanced, all old values of banned IRQs are forgotten.
irqbalance checks SCM_CREDENTIALS of sender (only root user is allowed to interact). Based on chosen
tools, ancillary message with credentials needs to be sent with request.
Homepage
https://github.com/Irqbalance/irqbalance