Date: Mon, 26 Mar 2018 17:22:48 -0700 From: John-Mark Gurney <jmg@funkthat.com> To: "Joseph H. Buehler" <jhpb@cox.net> Cc: "freebsd-net@freebsd.org" <freebsd-net@freebsd.org> Subject: Re: netmap ixgbevf max frame size Message-ID: <20180327002248.GQ75576@funkthat.com> In-Reply-To: <5AB25EF9.4080100@cox.net> References: <5AAC49BE.3030508@cox.net> <5AAC4A96.1040107@cox.net> <5AB01439.3090003@cox.net> <Q8MS1x00g3ftU9t018MSnu> <5AB25533.3020003@cox.net> <5AB25EF9.4080100@cox.net>
next in thread | previous in thread | raw e-mail | index | archive | help
Joseph H. Buehler wrote this message on Wed, Mar 21, 2018 at 09:32 -0400: > This turned out to be a limitation of the box we are using, there is apparently hardware between the ixgbevf chip and the fiber. I've written a program that will probe the sizes that work successfully, set the route's MTU properly. This is designed for FreeBSD, but should be adaptable to Linux, assuming it has similar features: https://github.com/jmgurney/automtud > > I am unable to send frames larger than 9216 bytes (destination MAC through trailing CRC inclusive) using ixgbevf hardware with latest netmap code (LINUX). > > > > What is the source of this limitation? From the chip datasheet it appears that much larger frames are supported. > > > > There is mention of 9216 in some of the driver source files but as an MTU, the max frame size is larger. -- John-Mark Gurney Voice: +1 415 225 5579 "All that I will do, has been done, All that I have, has not."
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20180327002248.GQ75576>