On Wed, 20 Oct 2010, xiaolin wrote:
> Dear friends, > > Could anyone tell the reason? > > > > I have three computers, denoted as A, B, C respectively. All with intel > GbE NIC. Let A send to B UDP packets (IP packet size is 1500bytes) . > The sending rate of A is about 880Mbps. Now I let C send to B UDP > packets also. > > The result is that A's sending rate is reduced to 440Mbps. C's sending > rate is reduced to 440Mbps. B's receiving rate is about 880Mbps. I think you're seeing the result of flow control packets. What kind of switch do you have? It probably forwards flow control packets (and it should not, but many simple switches do) > Could anyone tell me why A reduces its sending rate? e1000 drivers has > such the functionality of adjusting the sending rate? If you disable flow control with ethtool -A ethX autoneg off rx off tx off (and then maybe do ethtool -r ethX, depending on driver version it might be necessary) the problem should disappear. Jesse ------------------------------------------------------------------------------ Nokia and AT&T present the 2010 Calling All Innovators-North America contest Create new apps & games for the Nokia N8 for consumers in U.S. and Canada $10 million total in prizes - $4M cash, 500 devices, nearly $6M in marketing Develop with Nokia Qt SDK, Web Runtime, or Java and Publish to Ovi Store http://p.sf.net/sfu/nokia-dev2dev _______________________________________________ E1000-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/e1000-devel To learn more about Intel® Ethernet, visit http://communities.intel.com/community/wired
