From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rick Jones Subject: Re: [ofa-general] Re: IPoIB forwarding Date: Tue, 01 May 2007 15:12:08 -0700 Message-ID: <4637BB38.9020809@hp.com> References: <6.1.2.0.2.20070423160212.12db6400@mail.llnl.gov> <20070425124652.GG1624@mellanox.co.il> <6.1.2.0.2.20070426083410.1389d9e0@mail.llnl.gov> <20070426161409.GF15540@mellanox.co.il> <6.1.2.0.2.20070426095112.138e9a68@mail.llnl.gov> <20070426180618.GJ15540@mellanox.co.il> <6.1.2.0.2.20070427115435.13ea5ec0@mail.llnl.gov> <46325DF3.2050203@hp.com> <6.1.2.0.2.20070427152027.13fe46d0@mail.llnl.gov> <46327A07.1000404@hp.com> <6.1.2.0.2.20070427153952.13fc7d08@mail.llnl.gov> <4632894D.40705@hp.com> <20070428025117.a3b1200a.billfink@mindspring.com> <4634F49F.9030408@myri.com> <46365BD4.5060607@hp.com> <4637B9A4.2050103@myri.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Cc: Bryan Lawver , Linux Network Development list , Bill Fink , mst@dev.mellanox.co.il, general@lists.openfabrics.org To: Loic Prylli Return-path: In-Reply-To: <4637B9A4.2050103@myri.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: general-bounces@lists.openfabrics.org Errors-To: general-bounces@lists.openfabrics.org List-Id: netdev.vger.kernel.org Loic Prylli wrote: > On 4/30/2007 2:12 PM, Rick Jones wrote: > >> >> Speaking of defaults, it would seem that the external 1.2.0 driver >> comes with 9000 bytes as the default MTU? At least I think that is >> what I am seeing now that I've started looking more closely. >> >> rick jones > > > > That's the same for the in-kernel-tree code (9K MTU by default). > Assuming this is not wanted, I will submit a patch for that. While I like what that does for perrformance, and at the risk of putting words into the mouths of netdev, I suspect that 1500 bytes is indeed the desired default. It matches the IEEE specs, I've yet to see a switch which enabled "Jumbo Frames" by default, not everything out there even believes that Jubmo Frames means 9000 byte MTU etc etc etc. I think that 1500 bytes for an "Ethernet" device remains in line with the principle of least surprise. rick jones