Re: irq balancing; kernel vs. userspace

Zwane Mwaikambo
2003-04-20T20:07:41Z

On Sun, 20 Apr 2003, Sean Neakums wrote:

> I thought I'd play with the userspace IRQ-balancer, but booting with
> noirqbalance seems not to not balance. Possibly I misunderstand how
> this all fits together.
>
> $ uname -a
> Linux peng-33 2.5.68 #1 SMP Sun Apr 20 13:06:57 IST 2003 i686 unknown unknown GNU/Linux
> $ cat /proc/cmdline
> auto BOOT_IMAGE=default ro root=801 noirqbalance
> $ cat /proc/interrupts
> CPU0 CPU1
> 0: 853487 854900 IO-APIC-edge timer
> 1: 9 4 IO-APIC-edge i8042
> 2: 0 0 XT-PIC cascade
> 4: 15548 15161 IO-APIC-edge serial
> 8: 2 1 IO-APIC-edge rtc
> 9: 3 2 IO-APIC-level eth1
> 10: 1784 1805 IO-APIC-level via82cxxx, eth0
> 11: 10939 10860 IO-APIC-level aic7xxx
> 12: 39 21 IO-APIC-edge i8042
> NMI: 0 0
> LOC: 1708150 1708149
> ERR: 0
> MIS: 0

Local APICs before P4 by default arbitrated for interrupt handling, via a
round robin type scheme, this doesn't seem to be the case with P4 since the
Arbitration ID register is also gone now.

Zwane
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