Fwd: em0 performance subpar

[Adam Stylinski]

---------- Forwarded message ----------
From: Adam Stylinski <kungfujesus06 at gmail.com>
Date: Thu, Apr 28, 2011 at 11:21 AM
Subject: Re: em0 performance subpar
To: Steven Hartland <killing at multiplay.co.uk>


On Thu, Apr 28, 2011 at 04:08:31PM +0100, Steven Hartland wrote:
> You said your testing with iperf, what settings are you using?
>
> Flow control is not flowtable no, which could still result in
> a switch "issue" if linux and freebsd are setting different
> values by default, similarly with duplex / speed, I would recommend
> autoneg if your not already using.
>
> Have you tried without tso, rxcsum, txcsum & lro disabled?
>
>
> ----- Original Message -----
> From: "Adam Stylinski" <kungfujesus06 at gmail.com>
> To: "Steven Hartland" <killing at multiplay.co.uk>
> Cc: <freebsd-net at freebsd.org>
> Sent: Thursday, April 28, 2011 3:45 PM
> Subject: Re: em0 performance subpar
>
> I was using the default value for maxsockbuf, doesn't seem to hurt or
help.  The only value you've listed that I didn't have
> tweaked to a comparable value already was the nmbclusters, changing it
seems to have no effect, though.  vmstat -i should display
> my interrupts, which I don't think are particularly high.  I am most
definitely not CPU bound (utilization shows no hot CPUs), I
> have 16GB of memory and plenty allocated to the kernel, and I believe flow
control is enabled (should it not be?):
> net.inet.flowtable.enable: 1
>
> It's a 16 port netgear gigabit prosafe switch, and it's not likely to be
the problem (like I said, the Linux hosts have no issues
> with the same card).
>
>
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Just using the default settings with iperf.  Netblast is giving me similar
results.  Disabling TCP checksum offloading (transmit and receive) and large
receive offload have zero effect.

--
Adam Stylinski
PGP Key: http://pohl.ececs.uc.edu/~adam/publickey.pub
Blog: http://technicallyliving.blogspot.com
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