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