Date: Wed, 13 Aug 2008 21:35:44 -0700 From: "Jack Vogel" <jfvogel@gmail.com> To: Paul <paul@gtcomm.net> Cc: "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>, FreeBSD Stable List <freebsd-stable@freebsd.org> Subject: Re: HEADS UP: E1000 networking changes in STABLE/7.1 RELEASE Message-ID: <2a41acea0808132135oe9ebc6bk9423ac19f2e9f77a@mail.gmail.com> In-Reply-To: <48A3A2DA.8030404@gtcomm.net> References: <2a41acea0808131502y39879a22u39c472bd0b810fc2@mail.gmail.com> <48A3A2DA.8030404@gtcomm.net>
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On Wed, Aug 13, 2008 at 8:13 PM, Paul <paul@gtcomm.net> wrote: > Hi Jack. Will the em driver ever support the multiple hardware queues of > the 82571 or are we just stuck with the standard em driver? > Has there been any significant change in the em driver itself ? > I have a feeling that the 82571 should be in the igb driver but for some > reason it isn't. I am curious because we have a LOT of 4 port 82571 PCI-E > cards and they are not cheap. :] Hey Paul, You are right, quad port cards aren't cheap, Intel has sold them even back in a PCI-X based system. And the one you are talking about was released since I have been in this job, so pretty new :) However, they will never support multiple queues, the reason being that in order to do this you need multple MSI vectors, in other words, MSIX. Still, they are very handy, they do support MSI, but just one per interface. Oh, and I debated about where to make the cutoff line on the em/igb split and decided the best thing to do was to follow Linux. The biggest difference between the two drivers is that those in the igb use a different descriptor format, called 'advanced descriptors'. The split does NOT mean that em is now fixed. Quite the contrary, the em driver that was just MFC'd into STABLE has support for what I think is going to be the coolest new consumer adapter out there, called 82574, code name Hartwell, and also for ICH10. Both these two new interfaces have IEEE 1588 Precision Time Protocol support, something that is becoming important for networked multimedia applications. Oh, and Hartwell is the first adapter in the em driver that actually does multiqueue, although in a limited fashion, it does MSIX. This adapter is made at a lower cost point, but it has really nice features. I only wish the new motherboard that I bought had them rather than ICH9 but oh well :) I predict they are going to be selling like hotcakes before the end of year. I will continue to share fixes between the em and igb drivers as they are applicable. I still think a real legacy driver for the oldest adapters would be a good idea, just so they don't get broken by new development, with as many as we support regression testing is already not being done adequately. I just have not had time to think about this yet, it may be coming, it would probably be for everything that was not PCI Express. Hope the info was helpful, I'm always happy to answer questions, Jack
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