From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp.tuxdriver.com (charlotte.tuxdriver.com [70.61.120.58]) by dpdk.org (Postfix) with ESMTP id CEE4F7F3D for ; Wed, 8 Oct 2014 21:06:55 +0200 (CEST) Received: from cpe-098-026-066-094.nc.res.rr.com ([98.26.66.94] helo=localhost) by smtp.tuxdriver.com with esmtpsa (TLSv1:AES128-SHA:128) (Exim 4.63) (envelope-from ) id 1XbwgV-0008Mu-IE; Wed, 08 Oct 2014 15:14:10 -0400 Date: Wed, 8 Oct 2014 15:14:03 -0400 From: Neil Horman To: Thomas Monjalon Message-ID: <20141008191403.GB13306@hmsreliant.think-freely.org> References: <1405024369-30058-1-git-send-email-linville@tuxdriver.com> <20140926140855.GD3930@hmsreliant.think-freely.org> <20140929100553.GA12072@BRICHA3-MOBL> <4230474.fJnSGQJdQd@xps13> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4230474.fJnSGQJdQd@xps13> User-Agent: Mutt/1.5.23 (2014-03-12) X-Spam-Score: -2.9 (--) X-Spam-Status: No Cc: dev@dpdk.org Subject: Re: [dpdk-dev] [PATCH v2] librte_pmd_packet: add PMD for AF_PACKET-based virtual devices X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 08 Oct 2014 19:06:56 -0000 On Wed, Oct 08, 2014 at 05:57:46PM +0200, Thomas Monjalon wrote: > 2014-09-29 11:05, Bruce Richardson: > > On Fri, Sep 26, 2014 at 10:08:55AM -0400, Neil Horman wrote: > > > On Fri, Sep 26, 2014 at 11:28:05AM +0200, Thomas Monjalon wrote: > > > > 2014-09-16 16:16, Neil Horman: > > > > > On Fri, Sep 12, 2014 at 02:05:23PM -0400, John W. Linville wrote: > > > > > > Ping? Are there objections to this patch from mid-July? > > > > > > > > > > Thomas, Where are you on this? It seems like if you don't have any objections > > > > > to this patch, it should go in, in ilght of the lack of further commentary. > > > > > > > > 1) It doesn't appear as a top priority. > > > Thats your responsibility. Patches can't languish and rot on a list forever > > > just because others aren't willing to test it. If theres further testing that > > > you feel it needs, ask. But from my read, its been tested for functionality and > > > performance (though high performance is never expected from a AF_PACKET PMD). > > > Given that any one PMD will not affect the performance of another in isolation, > > > I'm not sure what more you're waiting for here. > > Yes, integration of new PMD must be accelerated. > > > > > 2) It's competing with pcap PMD and bifurcated PMD to come > > > > (http://dpdk.org/ml/archives/dev/2014-September/005379.html) > > > Regarding the pcap PMD, so? Its an alternate implementation that provides > > > different features with different limitations. The fact that they are simmilar > > > is irrelevant. If simmilarity was the test, then we wouldn't bother with the > > > bifurcated driver either, because the pcap pmd already exists. > > > > > > Regarding the bifurcated driver, you can't hold existing patches on the promise > > > of another pmd thats comming at an indeterminate time in the future. Theres no > > > reason not to take this now and deprecate it in the future if there is > > > sufficient overlap with the bifurcated driver, though to my point above, they > > > still address different needs with different limitations, so I don't see doing > > > so as necessecary. > > Yes, we'll discuss it when bifurcated driver will be released. > john Fastabend posted it to netdev just a few days ago. There have been some concerns raised, which he is trying to address. I'm watching how that goes. > > > > 3) There is no test associated with this PMD. > > > That would have been a great comment to make a few months back, though whats > > > wrong with testpmd here? That seems to be the same test that every other pmd > > > uses. What exactly are you looking for? > > I was thinking of testing behaviour with different kernel configurations and > unit tests for --vdev options. But it's not a major blocker. > Thats fine with me. If theres a set of unit tests that you have documentation for, I'm sure we would be happy to run them. I presume you just want all the pmd vdev option exercised? Any specific sets of kernel configurations? > > > > If one of this item becomes wrong, it should go in. > > > > > > > Currently, 2 projects are being initiated for validation (dcts) and > > > > documentation. Keeping new things outside of the DPDK core makes it > > > > clear that they have not to be supported by dcts and doc yet. > > > > So, it is better to have an external PMD, like memnic, acting as a > > > > staging area. > > > > > > > So, this brings up an excellent point - Validation and support. Commonly open > > > source projects don't provide support at the upstream HEAD. Those items are > > > applied and inforced by distributors. Theres no need to ensure that the > > > upstream head is always the most performance and stable point of the tree. Its > > > that need that keeps the development pace slow, and creates frustrations like > > > this one, where a patch sits unaddressed for long periods of time. Commonly the > > > workflow for most open source projects is for there to be a window of time where > > > visual review and basic functional testing are sufficient for acceptance into > > > the head of the tree. After the development window closes there is a > > > stabilization period where testing/validation is done to ensure that no > > > regressions have been encountered, optionally with a -next branch temporarily > > > being created to accept patches for upcomming future releases. If regressions > > > are found, its a simple matter in git to bisect back to the offending patch, > > > allow the contributing developer an opportunity to fix the issue, or to drop the > > > patch. Using a workflow like this we can have a reasonable balance of needs > > > (good patch turn around time, as well as reasonable testing). We've discussed > > > this when I posted the PMD_REGISTER_DRIVER patch months ago, and I thought you > > > were going to move in the direction of this workflow. What happened? > > Yes, we are moving to a "merge window" workflow. > That would be wonderful. I think separating the integration workflow from the test workflow is critical here to making sure that patch integration isn't unnecessecarily delayed. > > > > During this time, keeping this PMD separately will allow you to update it > > > > with a maintainer account in dpdk.org. I just need your SSH public key. > > > > > > > We've discussed this too, keeping PMDs maintained separately is a very bad idea. > > > Doing so means developers have to constantly be aware of changes to the core > > > tree and try to keep up individually. Integrating them all means that API > > > changes can be easily propogated to all PMD's when needed without making work > > > for many people. Its exactly the reason we encourage driver writers to open > > > source drivers in Linux, because not doing so closes developers off from the > > > free maintenence they get when optimizations are made to API's. And if you > > > follow the development model above, you don't need to worry about implied > > > support, as that correctly becomes a distributor issue. > > > > > > > > > Neil > > > > While not wanting to get too involved in the discussion, I'd just like to > > express my support for getting this new PMD merged in. > > If RedHat is committed for its maintenance, it could integrated in release 1.8. > But I'd like it to be renamed as pmd_af_packet (or a better name) instead of > pmd_packet. > John L. is on his way to plumbers at the moment, so is unable to comment, but I'll try to get a few cycles to change the name of the PMD around. And yes, I thought that maintenance was implicit. He's the author, of course he'll take care of it :). And I'll be glad to help Neil > Thanks > -- > Thomas >