From owner-freebsd-net Fri Jul 5 10:31: 8 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 11C3137B400 for ; Fri, 5 Jul 2002 10:31:04 -0700 (PDT) Received: from wall.polstra.com (wall-gw.polstra.com [206.213.73.130]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2053143E3B for ; Fri, 5 Jul 2002 10:31:03 -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 g65HV0T69099; Fri, 5 Jul 2002 10:31:00 -0700 (PDT) (envelope-from jdp@vashon.polstra.com) Received: (from jdp@localhost) by vashon.polstra.com (8.12.4/8.12.4/Submit) id g65HUxKW003600; Fri, 5 Jul 2002 10:30:59 -0700 (PDT) (envelope-from jdp) Date: Fri, 5 Jul 2002 10:30:59 -0700 (PDT) Message-Id: <200207051730.g65HUxKW003600@vashon.polstra.com> To: net@freebsd.org From: John Polstra Cc: bmilekic@unixdaemons.com Subject: Re: virtually contig jumbo mbufs (was Re: new zero copy sockets snapshot) In-Reply-To: <20020705132735.A873@unixdaemons.com> References: <20020619090046.A2063@panzer.kdm.org> <15653.35606.290023.621040@grasshopper.cs.duke.edu> <200207051645.g65Gj1lM003467@vashon.polstra.com> <20020705132735.A873@unixdaemons.com> 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 <20020705132735.A873@unixdaemons.com>, Bosko Milekic wrote: > > On Fri, Jul 05, 2002 at 09:45:01AM -0700, John Polstra wrote: > > The BCM570x chips (bge driver) definitely need a single physically > > contiguous buffer for each received packet. > > This is totally ridiculous for gigE hardware, IMO. It's a shame, I agree, though I don't think I'd call it totally ridiculous. Support of multiple buffers per packet is practically essential for transmitting (and the BCM570x chips do support that), but it's really just a convenience for receiving. > Do you know of other cards that can't do scatter gather DMA? No, but I'm only intimately familiar with two of the drivers. The Broadcoms (bge) can gather but cannot scatter, and the Intels (em/gx) can do both. 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