1IRQBALANCE(1) irqbalance IRQBALANCE(1)
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6 irqbalance - distribute hardware interrupts across processors on a mul‐
7 tiprocessor system
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10 irqbalance
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14 The purpose of irqbalance is distribute hardware interrupts across pro‐
15 cessors on a multiprocessor system in order to increase performance.
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19 -o, --oneshot
20 Causes irqbalance to be run once, after which the daemon exits
21 -d, --debug
24 Causes irqbalance to print extra debug information. Implies
25 --foreground
26 -f, --foreground
29 Causes irqbalance to run in the foreground (without --debug)
30 -h, --hintpolicy=[exact | subset | ignore]
33 Set the policy for how irq kernel affinity hinting is treated.
34 Can be one of:
35 exact irq affinity hint is applied unilaterally and never violated
37 subset irq is balanced, but the assigned object will be a subset of the
39 affintiy hint
40 ignore irq affinity hint value is completely ignored
42 The default value for hintpolicy is ignore
44 -p, --powerthresh=<threshold>
47 Set the threshold at which we attempt to move a cpu into power‐
48 save mode If more than <threshold> cpus are more than 1 standard
49 deviation below the average cpu softirq workload, and no cpus
50 are more than 1 standard deviation above (and have more than 1
51 irq assigned to them), attempt to place 1 cpu in powersave mode.
52 In powersave mode, a cpu will not have any irqs balanced to it,
53 in an effort to prevent that cpu from waking up without need.
54 -i, --banirq=<irqnum>
57 Add the specified irq to the set of banned irqs. irqbalance will
58 not affect the affinity of any irqs on the banned list, allowing
59 them to be specified manually. This option is addative and can
60 be specified multiple times. For example to ban irqs 43 and 44
61 from balancing, use the following command line: irqbalance
62 --banirq=43 --banirq=44
63 --deepestcache=<integer>
66 This allows a user to specify the cache level at which irqbal‐
67 ance partitions cache domains. Without specified, irqbalance
68 searches the available deepest cache. This can affect how
69 irqbalance builds up the CPU tree. For example, on a system
70 where all the CPU cores being within the same L3 cache domain,
71 one can let irqbalance build up the CPU tree on L2 cache by
72 using the following command line: irqbalance --deepestcache=2
73 -l, --policyscript=<script>
76 When specified, the referenced script will execute once for each
77 discovered irq, with the sysfs device path and irq number passed
78 as arguments. Note that the device path argument will point to
79 the parent directory from which the irq attributes directory may
80 be directly opened. The script may specify zero or more
81 key=value pairs that will guide irqbalance in the management of
82 that irq. Key=value pairs are printed by the script on stdout
83 and will be captured and interpreted by irqbalance. Irqbalance
84 expects a zero exit code from the provided utility. Recognized
85 key=value pairs are:
86 ban=[true | false]
88 Directs irqbalance to exclude the passed in irq from balancing
89 balance_level=[none | package | cache | core]
91 This allows a user to override the balance level of a given irq.
92 By default the balance level is determined automatically based
93 on the pci device class of the device that owns the irq.
94 numa_node=<integer>
96 This allows a user to override the numa node that sysfs indi‐
97 cates a given device irq is local to. Often, systems will not
98 specify this information in ACPI, and as a result devicesa are
99 considered equidistant from all numa nodes in a system. This
100 option allows for that hardware provided information to be over‐
101 ridden, so that irqbalance can bias irq affinity for these
102 devices toward its most local node. Note that specifying a -1
103 here forces irqbalance to consider an interrupt from a device to
104 be equidistant from all nodes.
105 -s, --pid=<file>
107 Have irqbalance write its process id to the specified file. By
108 default no pidfile is written. The written pidfile is automati‐
109 cally unlinked when irqbalance exits. It is ignored when used
110 with --debug or --foreground.
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114 IRQBALANCE_ONESHOT
115 Same as --oneshot
116 IRQBALANCE_DEBUG
119 Same as --debug
120 IRQBALANCE_BANNED_CPUS
123 Provides a mask of cpus which irqbalance should ignore and never
124 assign interrupts to. This is a hex mask without the leading
125 ’0x’, on systems with large numbers of processors each group of
126 eight hex digits is separated by a comma ’,’. i.e. ‘export
127 IRQBALANCE_BANNED_CPUS=fc0‘ would prevent irqbalance from
128 assigning irqs to the 7th-12th cpus (cpu6-cpu11) or ‘export
129 IRQBALANCE_BANNED_CPUS=ff000000,00000001‘ would prevent irqbal‐
130 ance from assigning irqs to the 1st (cpu0) and 57th-64th cpus
131 (cpu56-cpu63).
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135 SIGHUP Forces a rescan of the available irqs and system topology
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139 https://github.com/Irqbalance/irqbalance
140Linux Dec 2006 IRQBALANCE(1)