Date: Thu, 28 Apr 2011 08:39:57 -0400 From: Adam Stylinski <kungfujesus06@gmail.com> To: freebsd-net@freebsd.org Subject: Re: em0 performance subpar Message-ID: <BANLkTim1OdpK83YtkeoXKP_j=K99A-BD6A@mail.gmail.com> In-Reply-To: <20110428123847.GA85701@freebsdbox.adamsnet> References: <20110428072946.GA11391@zephyr.adamsnet> <4DB946CE.4030901@rdtc.ru> <20110428123847.GA85701@freebsdbox.adamsnet>
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[-- Attachment #1 --] ---------- Forwarded message ---------- From: Adam Stylinski <kungfujesus06@gmail.com> Date: Thu, Apr 28, 2011 at 8:38 AM Subject: Re: em0 performance subpar To: Eugene Grosbein <egrosbein@rdtc.ru> On Thu, Apr 28, 2011 at 05:51:58PM +0700, Eugene Grosbein wrote: > On 28.04.2011 14:29, 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 > > > > Looking at a comment in the source code this indicates that the card was not able to obtain enough transmit descriptors (but I've given the card the maximum of 4096 in my loader.conf tunable). Is this a bug or a performance regression of some kind? Does anybody have a fix for this? I tried another card with the same chip in a different box on 8-STABLE to no avail (the box I'm trying to improve performance on is on 8.2-RELEASE-p1). > > > > Anybody manage to make this card push above 600mbps in ideal network benchmarks? Any help would be gladly appreciated. > > Please show output of "vmstat -z|egrep 'ITEM|mbuf'" command after the test. > > Eugene Grosbein ITEM SIZE LIMIT USED FREE REQUESTS FAILURES mbuf_packet: 256, 0, 4096, 896, 531481, 0 mbuf: 256, 0, 1026, 10497, 3882824, 0 mbuf_cluster: 2048, 65768, 4992, 2998, 105908, 0 mbuf_jumbo_page: 4096, 12800, 0, 4462, 1261679, 0 mbuf_jumbo_9k: 9216, 6400, 0, 0, 0, 0 mbuf_jumbo_16k: 16384, 3200, 0, 0, 0, 0 mbuf_ext_refcnt: 4, 0, 0, 168, 1, 0 I'm willing to try compiling the module with EM_MULTIQUEUE on the test box to see if it makes a difference, but I read it can have issues with UDP traffic. -- Adam Stylinski PGP Key: http://pohl.ececs.uc.edu/~adam/publickey.pub Blog: http://technicallyliving.blogspot.com [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.17 (FreeBSD) iQIcBAEBAgAGBQJNuV/PAAoJED6sRHE6TvmndY8QAK5o5aWvV5UReZInSWQMdz2a ZjNogwGr6xEBWvwvffbYaXycJH1NxCSGXXaUEZHlTlDY4Gn4tK6yhdh8ikEn7o0c cDk+K/N5HW2QjBuo521cjO8nv0IRZzf6O6ftrjd/3AmTUbIxSuOK4qGuvrpNyQzS nkAUfRbgh31pIH4JL7Bji3Ys0GdwVRmOHIyoy8qeCA9rCzvX4Ra/BT1rpnhZ80ts 2zcYwPsyXwBkg/jP6LThym+zBZuA0OqmD7TDFtVa9Zc4LpCUolhd6c7wWM7qf0hU e9MT/3ETy+QpTh5dD+Z9OGrgjlleYvJRmBUcOBknUnudqxIRjBS87QsJcxxXi8p/ OxomLLUhGn8y3BRutGiauwgrjr8GwmlG7BXWSWWHlAGnqWgJLJAbxJCO7tcwfdqx pgwUlzympaQJpR6Pzn19WT0Y8CEzKO0+THx470qmUuDzgnBT4TPmeCJt1VGA/92Y efv30aX3eTqyCt14EMNhltKErj5PUmkhgTaeV8dp6TzCJabe/YdOSuz3zgKIHrA9 SEQkHaVb8BZHU/XqSahEQPusx1c5l2xYqSCXd+S+lZOu/9up7AJyfa0IsfFM9di8 oeOp4X7kQ3JNSCy9RKyUlts6jYhsG/NRXWy0Fr8JqpLdCGc/UdgtlA0Q1juMxdvJ kQDnnrWruQlwKwuU7S4I =5euX -----END PGP SIGNATURE-----
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