At 8:14 AM -0600 12/21/06, Chris Adams wrote: >Once upon a time, Les <hlhowell@xxxxxxxxxxx> said: >> Ethernet only works well when the network is utilized about 50%. > >I'm familiar with how Ethernet works, and this is not Ethernet that is a >problem. Properly configured switched Ethernet can work without errors >at much more than 50% (I do that every day). Gigabit Ethernet should >run much faster than 200Mbps. When I ran a similar test with a Fast >Ethernet interface, I saw similar "stuttering" behavior, but it still >averaged around 70-80Mbps. > >There is no router in my problem setup; this is two systems connected to >a switch (not a hub). Neither is running anything else (one is booted >in rescue mode). Both systems show full duplex 1000Mbps link with flow >control enabled (both have tg3 chips). I was going to try jumbo frames >to see what difference that made, but one system doesn't support jumbo >frames. > >The fact that Linux stops sending on the network sometimes and stops >reading the hard drive other times points directly to how the kernel is >caching writes to NFS (but I can't tell if it is the filesystem layer or >the network stack). Copy /dev/zero from each machine to the other, simultaneously? That would eliminate all of NFS, leaving mostly the kernel. -- ____________________________________________________________________ TonyN.:' The Great Writ <mailto:tonynelson@xxxxxxxxxxxxxxxxx> ' is no more. <http://www.georgeanelson.com/>
