From owner-freebsd-net Fri Jul 5 9:45: 6 2002 Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 35A2E37B400 for ; Fri, 5 Jul 2002 09:45:03 -0700 (PDT) Received: from wall.polstra.com (wall-gw.polstra.com [206.213.73.130]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2A0B243E09 for ; Fri, 5 Jul 2002 09:45:02 -0700 (PDT) (envelope-from jdp@polstra.com) Received: from vashon.polstra.com (vashon.polstra.com [206.213.73.13]) by wall.polstra.com (8.11.3/8.11.3) with ESMTP id g65Gj1T68881 for ; Fri, 5 Jul 2002 09:45:01 -0700 (PDT) (envelope-from jdp@vashon.polstra.com) Received: (from jdp@localhost) by vashon.polstra.com (8.12.4/8.12.4/Submit) id g65Gj1lM003467; Fri, 5 Jul 2002 09:45:01 -0700 (PDT) (envelope-from jdp) Date: Fri, 5 Jul 2002 09:45:01 -0700 (PDT) Message-Id: <200207051645.g65Gj1lM003467@vashon.polstra.com> To: net@freebsd.org From: John Polstra Subject: Re: virtually contig jumbo mbufs (was Re: new zero copy sockets snapshot) In-Reply-To: <15653.35606.290023.621040@grasshopper.cs.duke.edu> References: <20020619090046.A2063@panzer.kdm.org> <20020705002056.A5365@unixdaemons.com> <20020704231321.A42134@panzer.kdm.org> <15653.35606.290023.621040@grasshopper.cs.duke.edu> Organization: Polstra & Co., Seattle, WA Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org In article <15653.35606.290023.621040@grasshopper.cs.duke.edu>, Andrew Gallatin wrote: > Kenneth D. Merry writes: > > I suppose it would be good to see what NIC drivers in the tree can receive > > into or send from multiple chunks of data, and what their requirements are. > > (how many scatter/gather segments they can handle, what is the maximum MTU, > > etc.) > > If you're just looking at the code, then this would be hard. All the > current drivers (with the exception of em) are coded to take one > physically contiguous private buffer. I'm pretty sure that most of > them are capable of doing scatter DMA, but I don't have the > programming docs. The BCM570x chips (bge driver) definitely need a single physically contiguous buffer for each received packet. John -- John Polstra John D. Polstra & Co., Inc. Seattle, Washington USA "Disappointment is a good sign of basic intelligence." -- Chögyam Trungpa To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message