I've got several SMP machines, some running CentOS 4.3 and some running Fedora Core 4. All machine are kept fully updated. A few are Pentium3-based and a few are Pentium4-based. They are all running the irqbalance daemon.
The distribution of interrupts across CPUs is indeed kept balanced, yet even after months of uptime ps shows no CPU use whatsoever by irqbalance. This from a program that is supposed to wake up every 10 (?) seconds and examine the interrupt counts. Given that there is an IRQ balancing scheme in the kernel, I have to wonder if irqbalance is actually being used.
The man page for this program consists of a single-sentence description of what the program does. Nice.
Does irqbalance really do anything on contemporary Red Hat-based systems?
Thanks.