seastar - SeaStar Ethernet driver
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From: David Miller on 4 Feb 2010 18:20 From: "Kevin Pedretti" <ktpedre(a)sandia.gov> Date: Thu, 4 Feb 2010 16:01:04 -0700 > Please let me know if these issues are show-stoppers as far as inclusion > goes. We would like to get this open-source driver into the kernel so > us and others with Cray XT systems can start to benefit from it, and > continue to automatically track kernel API changes. I may let it in as-is, thanks for the explanations. Could you at least consider perhaps that since it isn't really ethernet, not pretending that it is may be something to look at? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Kevin Pedretti on 4 Feb 2010 19:50 On Thu, 2010-02-04 at 16:13 -0700, David Miller wrote: > From: "Kevin Pedretti" <ktpedre(a)sandia.gov> > Date: Thu, 4 Feb 2010 16:01:04 -0700 > > > Please let me know if these issues are show-stoppers as far as inclusion > > goes. We would like to get this open-source driver into the kernel so > > us and others with Cray XT systems can start to benefit from it, and > > continue to automatically track kernel API changes. > > I may let it in as-is, thanks for the explanations. > > Could you at least consider perhaps that since it isn't > really ethernet, not pretending that it is may be something > to look at? Sure, I'm open to doing this and would appreciate any example drivers you could point me at. We do need to keep the capability though of talking to Cray's existing proprietary "ethernet" over seastar driver, which the existing driver does. If we go this route of being a non-Ethernet device, do you think it would still be possible to support this? Kevin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Kevin Pedretti on 4 Feb 2010 20:10 On Thu, 2010-02-04 at 16:16 -0700, Alan Cox wrote: > - tcpdump etc once coaxed would display seastar frames not fake ethernet > - the config tools would actually report what it really was > - non IP layers and userspace won't keep trying to do things you don't > want (what does it do right now with vlans I wonder 8)) > - there will be no ARP confusion > > If it wants to stay compatible and pretend to be ethernet you probably > need a message type for "encapsulated ethernet", you can then encapsulate > anything not IP and stay compatible by keeping IP sent the way it is > now ? Thats if it wants to in the first place. I agree the current situation is rather confusing and a lot or most of the standard tools will break. I have used tcpdump with some success, but I'm sure there's lots of stuff broken. We do need to stay compatible with the existing proprietary driver. The usage model we're after is leaving all of the service nodes (nodes users login to, serve I/O, etc.) booted with the existing proprietary software and rebooting the compute nodes (99% of the nodes) with a modern Linux kernel running this open-source seastar driver. The compute nodes need to be able to communicate with each other and with the service nodes using IP (point-to-point). Users login to the service nodes and then, for example, can ssh to compute nodes, scp files to compute nodes, etc. Probably critical background: each service node and each compute node has a seastar NIC that directly connects to nearest neighbors, forming a 3-D torus. The only way for the nodes to communicate is via this network. I like the idea of encapsulating whole ethernet frames in a new message type. But won't the lack of broadcast (and multi-cast) still be an issue for most protocols? I also don't have much control over the seastar header, but can probably find an ignored bit somewhere to mark the new message type. Kevin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: David Miller on 4 Feb 2010 20:10
From: "Kevin Pedretti" <ktpedre(a)sandia.gov> Date: Thu, 4 Feb 2010 17:36:54 -0700 > Sure, I'm open to doing this and would appreciate any example drivers > you could point me at. I can't think of any sorry. > We do need to keep the capability though of talking to Cray's > existing proprietary "ethernet" over seastar driver, which the > existing driver does. If we go this route of being a non-Ethernet > device, do you think it would still be possible to support this? I don't think it will break communication with Cray's stuff. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |