Date: Thu, 28 Apr 2011 02:59:51 -0500 From: Adam Vande More <amvandemore@gmail.com> To: Adam Stylinski <kungfujesus06@gmail.com> Cc: freebsd-net@freebsd.org Subject: Re: em0 performance subpar Message-ID: <BANLkTin3%2BA7jDpnL1=2in_QH1O7-hKBhJw@mail.gmail.com> In-Reply-To: <20110428072946.GA11391@zephyr.adamsnet> References: <20110428072946.GA11391@zephyr.adamsnet>
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On Thu, Apr 28, 2011 at 2:29 AM, Adam Stylinski <kungfujesus06@gmail.com>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 > > Maybe try EM_MULTIQUEUE? http://lists.freebsd.org/pipermail/freebsd-net/2011-April/028664.html -- Adam Vande More
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