Author: Peter Salisbury Date: To: Hampshire LUG Discussion List Subject: Re: [Hampshire] APIC, interrupts and wired NIC
2008/12/30 Nick Chalk <nick@???>: > Peter Salisbury <peterthevicar@???> wrote:
>> I'm installing a Debian distro on a Fujitsu
>> LifeBook which has a built in 10/100 NIC using
>> the e100 module. All seems well except that I
>> can't get more than about 50k throughput. When I
>> investigated, the 'overruns' count in ifconfig
>> was steadily mounting which indicates the
>> machine wasn't responding quickly enough to
>> incoming packets on the LAN. With the CPU at
>> around 3% this seemed odd, so I looked at the
>> IRQ's and found that eth0 was sharing
>> /proc/irq/9 with ACPI. I rebooted with acpi=off
>> and was able to get the normal 7-800k
>> throughput.
>
> I've also seen performance problems with e100
> devices when they've been sharing interrupts.
>
> Is there a BIOS option to move one or other device
> onto a different IRQ? You may find that they're
> physically wired to the same line, in which case
> you won't be able to separate them.
>
> You might like to try a kernel with Message-
> Signalled Interrupts enabled - the IRQ will be
> sent over the PCI bus in that case. I think the
> e100 supports that.
Thanks Nick, I'll have a look at those.
ATB, Peter
