From owner-freebsd-net@FreeBSD.ORG Wed Aug 30 18:18:46 2006 Return-Path: X-Original-To: freebsd-net@freebsd.org 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 988C316A4E8 for ; Wed, 30 Aug 2006 18:18:46 +0000 (UTC) (envelope-from jfvogel@gmail.com) Received: from py-out-1112.google.com (py-out-1112.google.com [64.233.166.180]) by mx1.FreeBSD.org (Postfix) with ESMTP id 76F0B43D58 for ; Wed, 30 Aug 2006 18:18:44 +0000 (GMT) (envelope-from jfvogel@gmail.com) Received: by py-out-1112.google.com with SMTP id o67so372079pye for ; Wed, 30 Aug 2006 11:18:43 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=bV7d7adVKQ8/cE+pKTRTjvF2/tnG4yf4YWa3/oPRl6snNQrUYI6JgImWCZNotQ14HBgDzAYQwYiCfnOXvRvannadtFJTGPzQpKicY4n+Qk7hKswgn0M+rwvOGQw++/M5JXZJKzb5+1+HYtFyctUMV8WO1zq1wp70eKhY5sJHdew= Received: by 10.35.72.6 with SMTP id z6mr1529760pyk; Wed, 30 Aug 2006 11:18:43 -0700 (PDT) Received: by 10.35.119.1 with HTTP; Wed, 30 Aug 2006 11:18:43 -0700 (PDT) Message-ID: <2a41acea0608301118r3c9bcces1c5b20fe208d6e93@mail.gmail.com> Date: Wed, 30 Aug 2006 11:18:43 -0700 From: "Jack Vogel" To: "Andrew Gallatin" In-Reply-To: <17653.51598.910897.127606@grasshopper.cs.duke.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <2a41acea0608291624u4ee91cdej2d87aa19e2e5ba62@mail.gmail.com> <17653.51598.910897.127606@grasshopper.cs.duke.edu> Cc: freebsd-net , Alan Cox , freebsd-current , Mohan Srinivasan , Robert Watson Subject: Re: RFC: FreeBSD I/OAT 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: Wed, 30 Aug 2006 18:18:46 -0000 On 8/30/06, Andrew Gallatin wrote: > > Excellent! Can you share some of these results? I would love to try > it, but I don't have FreeBSD on any machine with I/OAT hardware. Prafulla had the results > I've taken a very quick look at it. Maybe I'm just being dense, > but I don't like the name "dma_" being in the global namespace. > Maybe things (like dma_*_list should be called at least > dmaengine_*_list, etc. I have no commitment to specifics in the namespace, so it can be changed to suit tastes. > There are some style(9) defects which I'm sure others who are more > proficient at style(9) than I am will point out (// comments, function > names not starting in column 0, etc). Same as above, minor things we can fix... > How deep would you expect so->dma_wait_queue to get? Would it make > sense to keep a pointer to the last item so that insertion is O(1), > rather than O(N)? Again, this is Prafulla's code, he should respond. > Would it be possible to have a sysctl tunable threshold, below which > the system does a normal uiomove? A normal copyout() will certainly > be faster at some point.. This sounds like a good idea. We only provided the stack client, because of interest by a specific customer, but there is potential for this engine to be used in a variety of places, for instance in VM. For more diverse usages the registration/client code would need to be enhanced, something like what Linux has now. That is doable later down the path... > Thanks for the great work! > > Drew Thanks for looking it over :) Jack