Re: Tyan S2466 MPX integrated ethernet interrupt happy

Andrew Morton (akpm@zip.com.au)
Fri, 22 Mar 2002 17:53:40 -0800


Shane Nay wrote:
>
> I have an S2466 with an integrated 3COM 3C905C ethernet controller.
> What I've noticed when streaming tons of data accross my internal LAN
> is that the ethernet driver appears to be sucking up tons of cycles.
>
> A quick investigation of /proc/interrupts shows-
> 0: 195949 192414 IO-APIC-edge timer
> 1: 5126 5129 IO-APIC-edge keyboard
> 2: 0 0 XT-PIC cascade
> 5: 0 0 IO-APIC-level usb-ohci
> 8: 1 0 IO-APIC-edge rtc
> 9: 4248819 4245969 IO-APIC-level eth0
> 10: 144865 145243 IO-APIC-level usb-ohci, nvidia, EMU10K1
> 12: 48546 48865 IO-APIC-edge PS/2 Mouse
> 14: 122395 121652 IO-APIC-edge ide0
> 15: 26286 26498 IO-APIC-edge ide1
> NMI: 0 0
> LOC: 388204 388212
> ERR: 0
> MIS: 4
>
> So, approximately 8.5 million ethernet interrupts. The system is
> noticably slower when streaming ethernet data, and it's sucking up a
> lot more processing time than on my other much slower other box.
> This box is running a stock 2.4.18 kernel from kernel.org (i.e. no
> custom hacks). It's running 2 1800+ XPs.

That all looks normal. Could you be more specific about
the performance problems? How much slower? Output from
`top' and `ps'? Any nasty messages in the system log?

Looking at the ethernet driver won't help, I expect - it's
as efficient as most any other driver. If there is a problem,
it lies elsewhere...

A kernel profile would be illuminating. Build the kernel with as few
modules as possible, boot the machine with `profile=1' and play
with readprofile.

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