Thomas Glanzmann wrote:
Hello,
[ resend because .config and the used kernel version was missing ]
Linux Kernel Version: Linus Vanilla Tree; .config attached.
I recently aquired a Lenovo (IBM) T60 with a e1000 network card. I
experience high latency with this networkcard: Pings last upto 1 second
where the ping should be around 25 ms. I googled a bit and found the
following:
- Enable NAPI, which didn't worked for me.
64 bytes from 192.168.0.223: icmp_seq=30 ttl=64 time=1004 ms
64 bytes from 192.168.0.223: icmp_seq=31 ttl=64 time=0.444 ms
64 bytes from 192.168.0.223: icmp_seq=32 ttl=64 time=1006 ms
64 bytes from 192.168.0.223: icmp_seq=33 ttl=64 time=0.739 ms
Someone reported this problem on the e1000 bug tracker at e1000.sf.net.
He also reported that the behaviour goes away completely if he disables the
in-kernel irq balancer:
: If I disable in kernel config Irq Balancing pings are
: much better but not the best :-)
:
: 64 bytes from 192.168.3.74: icmp_seq=29 ttl=64 time=12.7 ms
: 64 bytes from 192.168.3.74: icmp_seq=30 ttl=64 time=10.0 ms
: 64 bytes from 192.168.3.74: icmp_seq=31 ttl=64 time=7.3 ms
: 64 bytes from 192.168.3.74: icmp_seq=32 ttl=64 time=4.5 ms
that's a large difference from >> 1000ms, and I cannot suspect otherwise that
the kernel irqbalance is wreaking havoc in your system, trying to swap the
entire context between each core (t60 is a core duo) every second or so.
I've never believed much in the kernel irq balancer, the userspace daemon
written by Arjan van der Ven just does a much better job, so can you try to
disable the kernel irqbalancer?
> CONFIG_IRQBALANCE=y
turn that off ;)
Cheers,
Auke
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