Hide Forgot
Description of problem: My gigabit ethernet connection speed is 475Mbits/sec according to iperf (which uses about 85% cpu time on the Atom). I use a 5m Cat5E cable between a Realtek 8111DL on a Intel D945GSEJT (Atom N270, i686) and a Realtek RTL8111B / RTL8111C on a Asrock ALiveDual-eSATA2 (Athlon64 X2 5000+, x86_64). ethtool says that there is a full duplex connection. ifconfig says the MTU is 1500 (different values r worse) and the error rate is 0. i tried to offload some work to the nic on the Atom board, but the link stopped working or slowed down then... Version-Release number of selected component (if applicable): Linux neo.riddick.homeunix.org 2.6.35.11-83.fc14.i686 #1 SMP Mon Feb 7 07:04:18 UTC 2011 i686 i686 i386 GNU/Linux Linux vaako.riddick.homeunix.org 2.6.35.11-83.fc14.x86_64 #1 SMP Mon Feb 7 07:06:44 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux How reproducible: if the link is idle otherwise: always Steps to Reproduce: 1. connect the cable 2. start iperf Actual results: 475Mbits/sec Expected results: 800Mbits/sec..900Mbits/sec Additional info: 1. when i use nc or nfs i get almost the same result (45MB/sec) 2. is the Atom the bottleneck?
seems like ethernet is more complicated than i thought, so that the Atom cant do more than 475Mbit/sec, although it can read from /dev/zero with 10Gbit/sec... -arne
addendum: funnily i get 799Mbit/sec with the same Atom N270 board (fc15) and my new Intel Core i7 (fc16)... :-) *yay* -arne