# phpman > man > irqbalance(1)

[IRQBALANCE(1)](https://www.chedong.com/phpMan.php/man/IRQBALANCE/1/markdown)                                irqbalance                                [IRQBALANCE(1)](https://www.chedong.com/phpMan.php/man/IRQBALANCE/1/markdown)



## 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 multi‐
       processor 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.


### -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  wak‐
              ing up without need.


### -i, --banirq=<irqnum>
              Add the specified IRQ to the set of banned IRQs. irqbalance will not affect the affin‐
              ity of any IRQs on the banned list, allowing them to be specified manually.  This  op‐
              tion  is  additive 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**


### -m, --banmod=<module
              Add the specified module to the set of banned modules, similar to  --banirq.   irqbal‐
              ance  will  not  affect the affinity of any IRQs of given modules, allowing them to be
              specified manually. This option is additive and can be specified multiple  times.  For
              example to ban all IRQs of module foo and module bar from balancing, use the following
              command line: **irqbalance** **--banmod=foo** **--banmod=bar**


### -c, --deepestcache=<integer>
              This allows a user to specify the cache level at which irqbalance partitions cache do‐
              mains.   Specifying  a  deeper  cache  may  allow  a greater degree of flexibility for
              irqbalance to assign IRQ affinity to achieve greater performance increases,  but  set‐
              ting  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 or directory will execute once for each discov‐
              ered 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 at‐
              tributes directory may be directly opened.  Policy scripts specified need to be  owned
              and executable by the user of irqbalance process, if a directory is specified, non-ex‐
              ecutable files will be skipped.  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.   Irqbal‐
              ance  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  bal‐
              ance  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 re‐
              sult 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.

       Note that, if a directory is specified rather than a regular file, all files in
              the directory will be considered policy scripts, and executed on adding of an irq to a
              database.   If  such a directory is specified, scripts in the directory must addition‐
              ally exit with one of the following exit codes:

       _0_      This indicates the script has a policy for the referenced irq, and that further script
              processing should stop

       _1_      This  indicates  that the script has no policy for the referenced irq, and that script
              processing should continue

       _2_      This indicates that an error has occurred in the script,  and  it  should  be  skipped
              (further processing to continue)


### -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 be‐
              tween 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.
              If  not specified, irqbalance use mask of isolated and adaptive-ticks CPUs on the sys‐
              tem as the default value.  This is a hexmask without the leading ’0x’. On systems with
              large  numbers  of  processors, each group of eight hex digits 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    IRQBAL‐
              ANCE_BANNED_CPUS=ff000000,00000001‘ would prevent irqbalance from  assigning  irqs  to
              the  1st  (cpu0)  and  57th-64th cpus (cpu56-cpu63).  Notes: This environment variable
              will be discarded, please use IRQBALANCE_BANNED_CPULIST instead. Before deleting  this
              environment variable, Introduce a deprecation period first for the consider of compat‐
              ibility.


       **IRQBALANCE**___**BANNED**___**CPULIST**
              Provides a cpulist which irqbalance should ignore and never assign interrupts to.   If
              not  specified,  irqbalance use mask of isolated and adaptive-ticks CPUs on the system
              as the default value.


## SIGNALS
       **SIGHUP** Forces a rescan of the available IRQs and system topology.


## API
       irqbalance is able to communicate via socket and return  it's  current  assignment  tree  and
       setup,  as  well as set new settings based on sent values. Socket is abstract, with a name in
       form of **irqbalance<PID>.sock** , where <PID> is the process ID of irqbalance instance to commu‐
       nicate with.  Possible values to send:

       **stats**  Retrieve  assignment  tree  of IRQs to CPUs, in recursive manner. For each CPU node in
              tree, it's type, number, load and whether the save mode is active are sent.  For  each
              assigned  IRQ  type, it's number, load, number of IRQs since last rebalancing and it's
              class are sent. Refer to types.h file for explanation of defines.

       **setup**  Get the current value of sleep interval, mask of banned CPUs and list of banned IRQs.

### settings sleep <s>
              Set new value of sleep interval, <s> >= 1.

       **settings** **cpus** **<cpu**___**number1>** **<cpu**___**number2>** **...**
              Ban listed CPUs from IRQ handling, all old values of banned CPUs are forgotten.

### settings ban irqs <irq1> <irq2> ...
              Ban listed IRQs from being balanced, all old values of banned IRQs are forgotten.

       irqbalance checks SCM_CREDENTIALS of sender (only root user is allowed to  interact).   Based
       on chosen tools, ancillary message with credentials needs to be sent with request.


## HOMEPAGE
       <https://github.com/Irqbalance/irqbalance>




Linux                                         Dec 2006                                 [IRQBALANCE(1)](https://www.chedong.com/phpMan.php/man/IRQBALANCE/1/markdown)