The Planet Forums > eth0 interrupts not spanning across CPUs

Full Version: eth0 interrupts not spanning across CPUs

The Planet Forums > System Administration > Server Hardware

Snover

Jul 11 2005, 04:47 PM

I have a SuperReseller server with 2x2.4GHz Xeon processors. I have been noticing rather high interrupt loads in vmstat (over 1000/sec) and tried doing a little investigating to get to the root of the problem.
I noticed that A. all of the interrupts for the ethernet card are being sent to the first virtual processor only, and are not being shared among the CPUs, and B. the number of interrupts generated by eth0 is rather high. The system has an Intel e1000 network card and is running Debian Testing, using kernel 2.6.8-2-686-smp (there is a 2.6.10 update I'm holding back until I can test it).

CODE

# cat /proc/interrupts

CPU0 CPU1 CPU2 CPU3

0: 1645265455 3423810505 1645306700 1645291045 IO-APIC-edge timer

9: 0 0 0 0 IO-APIC-level acpi

15: 27 1 0 0 IO-APIC-edge ide1

177: 1048805038 0 0 0 IO-APIC-level eth0

185: 9561 40447961 53343831 157 IO-APIC-level 3ware Storage Controller

NMI: 0 0 0 0

LOC: 4065107265 4065107264 4065107260 4065107262

ERR: 0

MIS: 0

CODE

# cat /proc/net/dev

Inter-| Receive | Transmit

face |bytes packets errs drop fifo frame compressed multicast|bytes packets errs drop fifo colls carrier compressed

lo:661406885 8751485 0 0 0 0 0 0 661406885 8751485 0 0 0 0 0 0

eth0:3535330893 626929625 0 0 0 0 0 0 743467137 860537996 0 0 0 0 0 0

sit0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Any thoughts?

challii

Jul 11 2005, 04:57 PM

Most newish motherboards have direct links from onboard network card to cpu, so it could just be the way the board is designed?

Snover

Jul 18 2005, 06:43 PM

Does anyone else have insight?

gbock

Feb 25 2006, 04:49 AM

http://www.google.com/search?hl=en&lr=&q=e...ate&btnG=Search

ftp://download.intel.com/design/network/a...lnots/ap450.pdf

http://lwn.net/Articles/152989/

http://sourceforge.net/projects/e1000

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