From owner-freebsd-net@FreeBSD.ORG Tue Oct 30 05:49:17 2007 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 5AB3816A41A for ; Tue, 30 Oct 2007 05:49:17 +0000 (UTC) (envelope-from brian.mcginty@gmail.com) Received: from nz-out-0506.google.com (nz-out-0506.google.com [64.233.162.226]) by mx1.freebsd.org (Postfix) with ESMTP id 114E013C4BF for ; Tue, 30 Oct 2007 05:49:16 +0000 (UTC) (envelope-from brian.mcginty@gmail.com) Received: by nz-out-0506.google.com with SMTP id l8so1218004nzf for ; Mon, 29 Oct 2007 22:49:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:references; bh=SAnUVJMWgRnU6m1tXNelvKWQajkPkBfykmL8iBJPs/Q=; b=C4YfMda2Mc3tdCms/oPsGx4NRN5Q+xzLKPVKEINDjaHkktHzXqqSWz4LdCyb+8xJuqdGWrS0biYujm4yjSELE003otTYdbGaPuoD07G9nCTqTGKNGF9vk/Ad1vW4rWk4sFGnsOjteNP6RoEx5Pr0lN6gxfhVKtpv/MlLEw65eAw= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:references; b=Xtp192lRLw2PaXUIChlNHGyDLteyHAE0piLbwjenCxDQA57xv9cgs76NpcjyD2Hl4A4rtA6dmUc54dOaTIyLZPzcqVIy4nU/9vyqSVyOYNRRi+s9erPlQl7e6/K/tUi2cFVvxHBbM60jc9mDM8pNXQ83mBZJsUKZ8nIT/RXHqGY= Received: by 10.142.171.6 with SMTP id t6mr1566603wfe.1193721711258; Mon, 29 Oct 2007 22:21:51 -0700 (PDT) Received: by 10.142.163.17 with HTTP; Mon, 29 Oct 2007 22:21:51 -0700 (PDT) Message-ID: <601bffc40710292221k35a6927fh9dfaa217ae68e416@mail.gmail.com> Date: Mon, 29 Oct 2007 22:21:51 -0700 From: "Brian McGinty" To: "Jack Vogel" In-Reply-To: <2a41acea0710291045m6f1d2acw78c26a455ea3894d@mail.gmail.com> MIME-Version: 1.0 References: <2a41acea0710291045m6f1d2acw78c26a455ea3894d@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: "freebsd-net@freebsd.org" , FreeBSD Current , FreeBSD Stable List Subject: Re: RFC: Evolution of the em driver X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 30 Oct 2007 05:49:17 -0000 I prefer (2) - non-intrusive on em, and the new one doesn't have to deal with legacy or backward compatibility with em. Any commonality with ixgbe? Later Brian. On 10/29/07, Jack Vogel wrote: > > I have an important decision to make and I thought rather than just make > it and spring it on you I'd present the issues and see what opinions were. > > Our newer hardware uses new features that, more and more, require > parallel code paths in the driver. For instance, the 82575 (Zoar) uses > what are called 'advanced descriptors', this means different TX path. > The 7.0 em driver has this support in it, it just uses a function pointer > to handle it. > > When I add in multiqueue/RSS support it will add even more code > that functions this way. > > What the Linux team did was to split the newer code into a standalone > driver, they call it 'igb'. I had originally resisted doing this, but with > the development I have been working on the past month I am starting > to wonder if it might not be best to follow them. > > I see 3 possibilities and I'd like feedback, which would you prefer if > you have a preference and why. > > First, keep the driver as is and just live with multiple code paths > and features, possibly #ifdef'ed as they appear. > > Second, split the driver as Linux has into em and igb. The added > question then is how to split it, Linux made the line the use of > advanced descriptors, so Zoar and after, but I could also see a > case for having everything PCI-E/MSI capable being in the new > driver. > > Third, sort of a half-way approach, split up code but not the > driver, in other words offer different source files that can be > compiled into the driver, so you could have the one big jumbo > driver with all in there, or one that will only work with a subset > of adapters. This one would probably be the most work, because > its a new approach. > > Cheers, > > Jack > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" >