Date: Thu, 28 Apr 2011 14:52:59 +0100 From: "Steven Hartland" <killing@multiplay.co.uk> To: "Mike Tancsa" <mike@sentex.net>, "Adam Stylinski" <kungfujesus06@gmail.com> Cc: freebsd-net@freebsd.org Subject: Re: em0 performance subpar Message-ID: <B04EE072E7F04402AC289EFBF55E1D05@multiplay.co.uk> References: <20110428072946.GA11391@zephyr.adamsnet> <4DB965D8.7090906@sentex.net>
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Running em's here we regularly see them hitting pretty much line rate
although there are a lot of different em's
Here we have the following under 8.0+
em0@pci0:6:0:0: class=0x020000 card=0x000015d9 chip=0x10968086 rev=0x01 hdr=0x00
vendor = 'Intel Corporation'
device = 'Intel PRO/1000 EB (Intel PRO/1000 EB)'
class = network
subclass = ethernet
You don't say which OS version your running?
Regards
Steve
----- Original Message -----
From: "Mike Tancsa" <mike@sentex.net>
To: "Adam Stylinski" <kungfujesus06@gmail.com>
Cc: <freebsd-net@freebsd.org>
Sent: Thursday, April 28, 2011 2:04 PM
Subject: Re: em0 performance subpar
> On 4/28/2011 3:29 AM, Adam Stylinski wrote:
>> Hello,
>>
>> I have an intel gigabit network adapter (the 1000 GT w/chipset 82541PI) which performs poorly in Freebsd compared to the same
>> card in Linux. I've tried this card in two different freebsd boxes and for whatever reason I get poor transmit performance.
>> I've done all of the tweaking specified in just about every guide out there (the usual TCP window scaling, larger nmbclusters,
>> delayed acks, etc) and still I get only around 600mbps. I'm using jumbo frames, with an MTU of 9000. I'm testing this with
>> iperf. While I realize that this may not be the most realistic test, linux hosts with the same card can achieve 995Mbit/s to
>> another host running this. When the Freebsd box is the server, Linux hosts can transmit to it at around 800 something Mbit/s.
>> I've increased the transmit descriptors as specified in the if_em man page, and while that gave me 20 or 30 more mbit/s, my
>> transmit performance is still below normal.
>>
>> sysctl stats report that the card is trigger a lot of tx_desc_fail2:
>> dev.em.0.tx_desc_fail2: 3431
>
> Try the tests using the tools in /usr/src/tools/tools/netperf to
> generate / test udp traffic.
>
> Perhaps give the driver from HEAD a try. There are a few fixes to it. I
> back ported it to RELENG_8, but it should work on 8.2R as well.
>
> http://www.tancsa.com/em-723.tgz
>
> what does pciconf -lvc for your em NIC show ?
> also, vmstat -i
>
> ---Mike
>
>
>
> --
> -------------------
> Mike Tancsa, tel +1 519 651 3400
> Sentex Communications, mike@sentex.net
> Providing Internet services since 1994 www.sentex.net
> Cambridge, Ontario Canada http://www.tancsa.com/
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