Messages in this thread | | | Date | Tue, 27 Feb 2007 09:56:44 -0800 | From | Stephen Hemminger <> | Subject | Re: sky2 stable in 2.6.12-rc1 (but still performance problem)... |
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On Tue, 27 Feb 2007 11:31:58 +0000 "Daniel J Blueman" <daniel.blueman@gmail.com> 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@linux-foundation.org> - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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