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Date:      Thu, 21 Jul 2011 10:10:11 -0400
From:      "Michael W. Lucas" <mwlucas@blackhelicopters.org>
To:        Eduardo Morras <nec556@retena.com>
Cc:        questions@freebsd.org
Subject:   Re: em0 NIC slow on 8.2-p1 amd64?
Message-ID:  <20110721141011.GB47190@bewilderbeast.blackhelicopters.org>
In-Reply-To: <4D301C9702145855@>
References:  <20110720160432.GA41775@bewilderbeast.blackhelicopters.org> <4D6348DC01B1E406@> <20110720191640.GA42821@bewilderbeast.blackhelicopters.org> <4D301C9702145855@>

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On Wed, Jul 20, 2011 at 09:32:27PM +0200, Eduardo Morras wrote:
> At 21:16 20/07/2011, Michael W. Lucas wrote:
> 
> >It's at gigabit:
> >
> >em0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
> >
> >options=219b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,TSO4,WOL_MAGIC>
> >        ether 00:15:17:31:c8:fe
> >        inet xxxxxxx
> >        media: Ethernet autoselect (1000baseT <full-duplex>)
> >        status: active
> 
> All seems to be ok, try a netstat -I em0 -d  (it's a capital 'i') to 
> get statistics. If too much packets are dropped recheck cables.
> 
> Other options:
> 
> a) 30 MB/s looks very strange, do you have pf or similar with a filter rule?
> b) Have you checked your disk i/o performance?
> c) If you generate the data dinamically, may be your producer app is 
> the problem.
> 
> About the em specific problem under 8.2 you cite, others can guide 
> better than me.
> 
> HTH

No obvious errors on netstat:

netstat -I em0 -d
Name    Mtu Network       Address              Ipkts Ierrs Idrop    Opkts Oerrs  Coll Drop
em0    1500 <Link#1>      00:15:17:31:c8:fe 11709782     0     0  6855755     0     0    0 
em0    1500 139.171.199.0 data5-vm           9546994     -     -  7584135     -     -    - 

PF is running, but disabling it makes no difference in throughput.

Disk is mostly idle... not saying it can't be disk, mind you, but
local disk-to-disk copies go much more quickly. I'm testing by copying
an ISO.

And as far as me knowing "many more things," well, if I knew what the
problem was, I wouldn't be begging for help like any other user.  :-)

Thanks,
==ml

-- 
Michael W. Lucas 	
http://www.MichaelWLucas.com/, http://blather.MichaelWLucas.com/
Latest book: Network Flow Analysis http://www.networkflowanalysis.com/
mwlucas@BlackHelicopters.org, Twitter @mwlauthor



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