IRQBALANCE(1)irqbalanceIRQBALANCE(1)NAMEirqbalance - distribute hardware interrupts across processors on a mul‐
tiprocessor system
SYNOPSISirqbalanceDESCRIPTION
The purpose of irqbalance is distribute hardware interrupts across pro‐
cessors on a multiprocessor system in order to increase performance.
OPTIONS--oneshot
Causes irqbalance to be run once, after which the daemon exits
--debug
Causes irqbalance to print extra debug information. Implies
--foreground
--foreground
Causes irqbalance to run in the foreground (without --debug)
--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
--powerthresh=<threshold>
Set the threshold at which we attempt to move a cpu into power‐
save 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.
--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
--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. 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 indi‐
cates 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 over‐
ridden, 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.
--pid=<file>
Have irqbalance write its process id to the specified file. By
default no pidfile is written. The written pidfile is automati‐
cally unlinked when irqbalance exits.
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
Homepage
http://code.google.com/p/irqbalance
Linux Dec 2006 IRQBALANCE(1)
