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.

       -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 affinity 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 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.

       hintpolicy=[exact | subset | ignore ]
              This  allows  a user to override the globally set hintpolicy for a given irq.  Use is identical to
              the --hintpolicy setting, but applied per irq

       -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.

Homepage

       https://github.com/Irqbalance/irqbalance

Linux                                               Dec 2006                                       IRQBALANCE(1)