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IRQBALANCE(1)                                         irqbalance                                        IRQBALANCE(1)

       irqbalance - distribute hardware interrupts across processors on a multiprocessor system


       The  purpose  of  irqbalance is distribute hardware interrupts across processors on a multiprocessor system in
       order to increase performance.

       -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

              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.

              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.

              Same as --oneshot

              Same as --debug

              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).

       SIGHUP Forces a rescan of the available irqs and system topology


Linux                                                  Dec 2006                                         IRQBALANCE(1)