Date: Mon, 7 Nov 2011 09:59:53 -0800 From: YongHyeon PYUN <pyunyh@gmail.com> To: Michael =?iso-8859-1?B?TGHf?= <bevan@bi-co.net> Cc: freebsd-net@freebsd.org Subject: Re: Gigabit Ethernet performance with Realtek 8111E Message-ID: <20111107175953.GA1646@michelle.cdnetworks.com> In-Reply-To: <20111106234054.GB1906@michelle.cdnetworks.com> References: <1320494003.19667.41.camel@bevan-pc.fritz.box> <20111106234054.GB1906@michelle.cdnetworks.com>
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On Sun, Nov 06, 2011 at 03:40:54PM -0800, YongHyeon PYUN wrote: > On Sat, Nov 05, 2011 at 12:53:23PM +0100, Michael La?? wrote: > > Hi! > > > > I've got a small NAS with Intel D525MW (Atom) board inside using FreeBSD > > 9.0-RC1 as operating system. It has an onboard Realtek 8111E ethernet > > adapter. I'm experiencing heavy performance problems when transfering > > files from a specific PC in my network to that NAS. I did the following > > tests by transfering large amount of data between the diferrent machines > > (using dd and nc): > > > > NAS -> Linux1: ~ 400Mbit/s > > NAS -> Linux2: ~ 400Mbit/s > > Linux1 -> NAS: heavy fluctuation, between 700Mbit/s and 0bit/s > > Linux2 -> NAS: ~ 400Mbit/s > > Linux1 -> Linux2: ~ 400Mbit/s > > Linux2 -> Linux1: ~ 400Mbit/s > > > > As you can see everythink works fine except for transfering data from > > Linux1 to that NAS box. The following graph shows the problem: > > http://dl.dropbox.com/u/25455527/network-problems.png > > > > While the transfer rate drops to zero the NAS also has a very bad ping > > up to one second. Ping of Linux1 is perfectly fine during these outages. > > > > I also had a quick look on the data stream with wireshark on Linux1 and > > it shows a lot of TCP Dup ACK (up to 263 Dup ACKs created by NAS for one > > frame). > > > > What can be eliminated as a cause is: > > - Switch (I tried connecting Linux1 and NAS directly) > > - Cable (I changed that a few times) > > - Harddisk I/O (I'm only writing from /dev/zero to /dev/null) > > > > The sevirity of that problem varies from one minute to another but can > > always be reproduced with a few tries. > > > > When limiting either NAS or Linux1 to 100Mbit I'm getting a steady > > transfer rate of about 90Mbit/s. > > Some revisions of RealTek controller have FIFO overrun issue but > I'm not sure whether you're seeing the issue. Try enabling flow > control and see whether that makes any difference. You can enable > it by issuing 'ifconfig re0 media flow'. This should be read as 'ifconfig re0 mediaopt flow'. > > > When decreasing the MTU on NAS to 1200 the problem seems to disappear, > > getting a transfer rate of about 160Mbit/s. > > > > ifconfig re0: > > > re0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500 > > > options=388b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWCSUM,WOL_UCAST,WOL_MCAST,WOL_MAGIC> > > > ether 38:60:77:3e:af:a5 > > > inet 192.168.178.54 netmask 0xffffff00 broadcast 192.168.178.255 > > > nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL> > > > media: Ethernet autoselect (1000baseT <full-duplex>) > > > status: active > > > > pciconf -lv: > > > re0@pci0:1:0:0: class=0x020000 card=0xd6258086 chip=0x816810ec rev=0x06 hdr=0x00 > > > vendor = 'Realtek Semiconductor Co., Ltd.' > > > device = 'RTL8111/8168B PCI Express Gigabit Ethernet controller' > > > class = network > > > subclass = ethernet > > > > Show me the dmesg output. RealTek uses the same device PCI ids so it's > impossible to know which controller you have from the pciconf(8) > output. > > > Because Linux1 seems to be involved in that problem: It's running Linux > > 3.0 and it has an "Atheros Communications AR8121/AR8113/AR8114" onboard. > > > > Does anyone have an idea what could be the problem here? Decreasing the > > MTU is some kind of solution but the performance is still not optimal > > and a MTU of 1500 should be no problem. > > > > Greetings, > > Michael Laß
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