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. -- 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
