> On Tue, Apr 15, 2008 at 09:06:44PM +0300, Anton Titov wrote:
>> I use Linux for serving a huge amount of static web on few servers. When
>> network traffic goes above 2Gbit/sec ksoftirqd/5 (not every time 5, but
>> every time just one) starts using exactly 100% CPU time and packet
>> packet loss starts preventing traffic from going up. When the network
>> traffic is lower than 1.9Gbit ksoftirqds use 0% CPU according to top.
>>
>> Uplink is 6 gigabit Intel cards bonded together using 802.3ad algorithm
>> with xmit_hash_policy set to layer3+4. On the other side is Cisco 2960
>> switch. Machine is with two quad core Intel Xeons @2.33GHz.
>>
>> Here goes a screen snapshot of "top" command. The described behavior
>> have nothing to do with 13% io-wait. It happens even if it is 0%
>> io-wait.
>>
http://www.titov.net/misc/top-snap.png
>>
>> kernel configuration:
>>
http://www.titov.net/misc/config.gz
>>
>> /proc/interrupts, lspci, dmesg (nothing intresting there), ifconfig,
>> uname -a:
>>
http://www.titov.net/misc/misc.txt.gz
>>
>> Is it a Linux bug or some hardware limitation?
>
> possibly some missing parameters when loading your e1000 drivers.
> e1000 NICs support interrupt rate limitation, which proves very
> efficient in cases such as yours. I'm used to limit them to about
> 5k ints/s. Do a "modinfo e1000" to get the parameter name, I don't
> have it quite right in mind.
>
> Also, I've CCed linux-net.
