On Tue, 27 Feb 2007 11:31:58 +0000 "Daniel J Blueman" <daniel.blueman@xxxxxxxxx> wrote: > Hi Stephen, > > 2.6.21-rc1 is the first kernel where my SysKonnect Yukon 2 hardware > with the sky2 v1.13 driver is stable under moderate load. Before a few > GBs of data going over my GigE network quickly with NFSv4 would cause > transmit timeouts previously, but now fine. > > I am still observing a performance problem - feels like a wmb() or > some buffer flushing is missing somewhere - disabling processor clock > scaling reduces the problem a bit, but does not eliminate it. That seems odd, if it was a missing barrier you would see data corruption. Are there checksum errors? You might be seeing hardware flow control. Look at ethtool -S eth0 output. Previously, transmit flow control was broken > What are your preferred way of checking performance? I think that the > TCP send window can grow enough even if ACKs are delayed due to this > problem, such that TCP does not immediately demonstrate this issue. I > could restrict the window scaling factor, so it would be bound by the > data->ACK round-trip latency, which /should/ be low, but I've been > observing it higher. Maybe I try this. iperf is easiest. > I'll see what I get with iperf UDP also, since this shows min, max, > avg UDP packet latency IIRC. > > Thanks for your great work so far though! > Dan -- Stephen Hemminger <shemminger@xxxxxxxxxxxxxxxxxxxx> - To unsubscribe from this list: send the line "unsubscribe linux-net" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
