1IRQBALANCE(1) irqbalance IRQBALANCE(1)
2
6 irqbalance - distribute hardware interrupts across processors on a mul‐
7 tiprocessor system
8
10 irqbalance
11
14 The purpose of irqbalance is distribute hardware interrupts across pro‐
15 cessors on a multiprocessor system in order to increase performance.
16
19 --oneshot
20 Causes irqbalance to be run once, after which the daemon exits
21 --debug
24 Causes irqbalance to run in the foreground and extra debug
25 information to be printed
26
29 IRQBALANCE_ONESHOT
30 Same as --oneshot
31 IRQBALANCE_DEBUG
34 Same as --debug
35 IRQBALANCE_BANNED_CPUS
38 Provides a mask of cpus which irqbalance should ignore and never
39 assign interrupts to
40
43 The purpose of irqbalance is to distribute interrupts accross cpus in
44 an smp system such that cache-domain affinity is maximized for each
45 irq. In other words, irqbalance tries to assign irqs to cpu cores such
46 that each irq stands a greater chance of having its interrupt handler
47 be in cache when the irq is asserted to the cpu. This raises a few
48 interesting cases in which the behavior of irqbalance may be non-intu‐
49 itive. Most notably, cases in which a system has only one cache
50 domain. Nominally these systems are only single cpu environments, but
51 can also be found in multi-core environments in which the cores share
52 an L2 cache. In these situations irqbalance will exit immediately,
53 since there is no work that irqbalance can do which will improve inter‐
54 rupt handling performance. This is normal and not cause for concern.
55 For more information regarding irqbalance, please visit http://irqbal‐
56 ance.org/
57Linux Dec 2006 IRQBALANCE(1)