IRQBALANCE(1) irqbalance IRQBALANCE(1)
NAME
irqbalance - distribute hardware interrupts across processors on a multiprocessor system
SYNOPSIS
irqbalance
DESCRIPTION
The purpose of irqbalance is 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)
-h, --hintpolicy=[exact | subset | ignore]
Set the policy for how irq kernel affinity hinting is treated. Can be one of:
exact irq affinity hint is applied unilaterally and never violated
subset irq is balanced, but the assigned object will be a subset of the affintiy hint
ignore irq affinity hint value is completely ignored
The default value for hintpolicy is ignore
-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 power‐
save 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. Without
specified, irqbalance searches the available deepest cache. This can affect how irqbalance builds up
the CPU tree. For example, on a system where all the CPU cores being within the same L3 cache domain,
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 devicesa 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.
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. This is a hex
mask without the leading ’0x’, on systems with large numbers of processors each group of eight hex dig‐
its is separated by a comma ’,’. i.e. ‘export IRQBALANCE_BANNED_CPUS=fc0‘ would prevent irqbalance from
assigning irqs to the 7th-12th cpus (cpu6-cpu11) or ‘export IRQBALANCE_BANNED_CPUS=ff000000,00000001‘
would prevent irqbalance from assigning irqs to the 1st (cpu0) and 57th-64th cpus (cpu56-cpu63).
SIGNALS
SIGHUP Forces a rescan of the available irqs and system topology
Homepage
https://github.com/Irqbalance/irqbalance
Linux Dec 2006 IRQBALANCE(1)
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