On Thu, Feb 15, 2007 at 05:50:30PM -0500, Lennart Sorensen wrote: > I have encountered a strange behaviour with the pcnet32. > > I am transfering data from a server to a client routing it through my > router. The router has 2 ethernet ports, both of which are amd 972 > chips (pcnet32). The transfer has so far been either http or ftp (both > see the same problem). I transfer lots of data, and after a while (I > have seen anywhere from 200 to 700MB or so) the speed suddenly drops to > less than 1KB/s. If I ping from the router to the server, the ping > requests go out normally (seen by tcpdump on the server) every second, > but on the router the replies are not seen by the kernel for multiple > seconds. Sometimes I will see 3 ping replies together, sometimes 5 or > even 10. The turn around times will show 10500, 9500, 8500, ..., 500ms > for the packets received in a batch. ifconfig on the router shows the > packet receive counts showing up in lumps, just as ping does, and > tcpdump on the interface on the router. > > Doing ifconfig down and up on the port connecting to the server makes > the problem clear and it can handle another pile of data before the > problem reappears. > > The CPU on the router is not fast enough to ensure there won't ever be > dropped packets at 100Mbps. When I force the port to the server to > 10Mbps I have no problems at all. > > Replacing the port to the server with an rtl8139 doesn't show any > problems at 100Mbps, although the transfer rate drops from 6500KBps to > 4000KBps compared to using the pcnet32. > > Kernel used so far is 2.6.16 and 2.6.18. > > I have a tulip card I intend to try with as well just to see if it > affects anything other than the pcnet32. > > Does anyone have any hints as to what part of the code to look at for > changes made by doing ifconfig eth1 down; ifconfig eth1 up? Any ideas > as to what could make the reception of packets suddenly get very very > slow? > > On one pass where I was running tcpdump on the router, I saw a wrap of > the sequence number right before the problem occoured, but that has not > been the case every time as far as I can tell, so I am not sure if that > is related to the problem at all.
I have run some tests using 2.6.8 now, and so far it hasn't failed. Still investigating... -- Len Sorensen - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
