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" <m...@sentex.net>
To: "Adam Stylinski" <kungfujesu...@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, m...@sentex.net
Providing Internet services since 1994 www.sentex.net
Cambridge, Ontario Canada http://www.tancsa.com/
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