Date: Sun, 28 Jul 2013 16:18:20 -0400 From: Scott Long <scottl@netflix.com> To: Jack Vogel <jfvogel@gmail.com> Cc: "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>, "Alexander V. Chernikov" <melifaro@freebsd.org>, Andre Oppermann <andre@freebsd.org>, Luigi Rizzo <rizzo@iet.unipi.it> Subject: Re: Recommendations for 10gbps NIC Message-ID: <55F6FD95-0634-4371-9384-14B8E8D74C6E@yahoo.com> In-Reply-To: <CAFOYbcm%2BZdn%2BYKGNCaW53P_4FDNWVuK%2BHYYZWYVkq4%2B3yJubaQ@mail.gmail.com> References: <51F0386D.2000709@acm.poly.edu> <51F16A07.9030505@FreeBSD.org> <1374852658.90079.YahooMailNeo@web121601.mail.ne1.yahoo.com> <51F2A313.9070105@FreeBSD.org> <alpine.LRH.2.03.1307261646050.25254@nber.org> <1374876857.42890.YahooMailNeo@web121603.mail.ne1.yahoo.com> <51F37E97.3090203@FreeBSD.org> <CA%2BhQ2%2BgQxdNM1o_rScuyPb_T9sm%2B=gEF1dUa5aknfUYrO4K9HA@mail.gmail.com> <51F387E8.6090704@FreeBSD.org> <51F3F3BA.20604@freebsd.org> <CAFOYbcm%2BZdn%2BYKGNCaW53P_4FDNWVuK%2BHYYZWYVkq4%2B3yJubaQ@mail.gmail.com>
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On Jul 28, 2013, at 2:42 PM, Jack Vogel <jfvogel@gmail.com> wrote: > On Sat, Jul 27, 2013 at 9:22 AM, Andre Oppermann <andre@freebsd.org> = wrote: >=20 >> On 27.07.2013 10:42, Alexander V. Chernikov wrote: >>=20 >>> On 27.07.2013 12:15, Luigi Rizzo wrote: >>>=20 >>>> On Sat, Jul 27, 2013 at 10:02 AM, Alexander V. Chernikov >>>> <melifaro@freebsd.org> wrote: >>>> This makes me curious because i believe people have used netmap = with >>>> the 82598 and achieved close to line rate even with 64-byte = frames/one >>>> port, >>>> and i thought (maybe I am wrong ?) the various 2-port NICs use 4 = lanes >>>> per port. >>>> So the number i remember does not match with your quote of 2.5Gt/s. >>>> Are all 82598 using 2.5GT/s (which is a gen.1 speed) instead of 5 ? >>>>=20 >>>>=20 >>=20 >>> Quoting 82598EB datasheet: >>> The PCIe v2.0 (2.5 GT/s) interface is used by the 82598EB as a host >>> interface. It supports x8, x4, >>> x2 and x1 configurations at a speed of 2.5 GHz. The maximum = aggregated >>> raw ban.. >>>=20 >>> Actually I discovered this exactly with netmap and 82598*-DA2 NIC :) >>>=20 >>=20 >> Discussing the 82598 is moot because it has been replaced with the = 82599 >> which supports x1-x8 at 5 GT/s. AFAIK you can't event buy the 82598 >> anymore. >>=20 >>=20 > Yes, and the new quad port adapters on PCIE Gen 3 give you 8GT/s = bandwidth > for > the device. I'm not sure if you could buy the 82598 but I surely would = not > recommend > it to anyone :) FWIW, sometimes these kinds of cards are interesting if your primary = interest is link failover instead of aggregate link speed. If the 82598 generated = less heat and/or consumed less power, or was significantly cheaper than more = modern offerings, it can still be attractive. Scott
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