<font face="arial" size="2"><p style="margin:0;padding:0;">I'll see about setting a login up for you - it's a bit complicated because the cluster is not exposed at the moment, so I need to secure it and expose it. I don't want to distract from feature completion... so it may be a few days (given that I'm busy during the week mostly with my day job at SAP, which involves systems engineering experiments with *really big* computing systems - my personal research toy there is 400 Westmere-EX cores with 5 TB of RAM, and 30 TB of PCIe Flash, and that's on the small end.... my team runs several other, larger systems of the same sort for "production" research :-) It runs Linux, of course. )</p>
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<p style="margin:0;padding:0;">My focus is related to dense mesh stuff, because scalable urban/mobile usage is the big wall for radio internetworking after IPv6 and controlled latency (bufferbloat). But actually I'm not trying to solve the whole "decentralized mesh" problem - what I'm trying to do is do propagation monitoring and modeling in real home environments on all 2.4 and 5 GHz channels (and maybe create a tool for that). It's my opinion that we need to understand a lot more about real-world physics *as seen by real radios*, and without that, we can't really design protocols for adaptive, cooperative use of these license-by-rule bands.</p>
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<p style="margin:0;padding:0;">The physics problem is one that may never be addressable by academic researchers - they don't have the ability to reach into homes, apartments, businesses, etc. to do the experiments. But an open, modern home router that anyone can buy for at most a couple hundred bucks can provide that platform. It's my "Internet 3 experiment". I firmly believe you need to do systems engineering experiments before designing answers. I can't use smartphones or commercial home routers to do this.</p>
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<p style="margin:0;padding:0;">Of course, once I've created a way to measure real-time propagation, the next step will be to create cooperation/adaptatation protocols (not just routing, but the complement of routing - where not to transmit given the physical environment, kind of "real-time radio engineering" to maximize utilization among the systems).</p>
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<p style="margin:0;padding:0;">David</p>
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<p style="margin:0;padding:0;">-----Original Message-----<br />From: "Dave Taht" <dave.taht@gmail.com><br />Sent: Monday, April 30, 2012 11:50am<br />To: dpreed@reed.com<br />Cc: "Outback Dingo" <outbackdingo@gmail.com>, cerowrt-devel@lists.bufferbloat.net<br />Subject: Re: Pointers on build setup?<br /><br /></p>
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<p style="margin:0;padding:0;">On Mon, Apr 30, 2012 at 8:14 AM, <dpreed@reed.com> wrote:<br />> Regarding builds - can someone who is building cerowrt from source<br />> (including kernel) point me at the recipe for building it completely from<br />> scratch?<br /><br />We have most of a build script that has worked at various points in time,<br />at the moment, I doubt it's correct. Ketan posted some mods recently...<br /><br />as things stand today, it's kind of fiddly, and requires multiple attempts<br />at getting the .config right, there's a few tool dependencies, etc.<br /><br />As soon as I hit feature complete - and had hardware that could turn<br />around builds fast enough - I'd planned to fix that up.<br /><br />In the interim...<br /><br />I can get a correct build setup for you in 10 minutes, if you give me a login.<br />Certainly having a script that 'just works', and is a one liner, has<br />been a goal, once things get more stable. Which I would hope be late<br />this week. Hopefully.<br /><br />I note I have not checked in all the 'fixes' to the ipv6 alignment<br />issue (bugs 360, 371, 379) in the past week, as alternatives are being<br />discussed on the openwrt-devel list.<br /><br />> Besides running 3.3-2 on a 3800, I've begun my project to validate that<br />> Cerowrt can run on my ubnt RouterStation Pro box, which is preliminary to<br />> doing some experimentation on dense scalability that interests me. I<br /><br />If you are talking about what I call the 'dense mesh' problem, the predecessor<br />project to cerowrt had it's original genesis in trying to solve the<br />meltdown issues olpc had with 802.11s.<br /><br />"Diversity routing" seemed to be an answer.<br /><br />www.pps.jussieu.fr/~jch/software/babel/wbmv4.pdf<br /><br />And the routerstation pro (3 radios! ooh!) is a perfect platform to be<br />trying that on.<br />Juliusz was looking into doing experiments on that hardware...<br /><br />Sadly it shares the unaligned ipv6 problem that we've been struggling to solve,<br />and the max thruput is less than what those 3 radios could achieve.<br /><br />> verified that it runs the latest stable Backfire release of OpenWRT this<br />> weekend, and it does so quite well.<br />><br />><br />><br />> My own private home build server is (essentially) a cluster of two AMD8160<br />> 8-core 32 GB servers connected with 40 Gb/s Infiniband and a 6-way RAID5<br />> storage array on one of them that gives quite nice read performance. I'm<br />> not worried about how long it takes to do a build...<br /><br />I will note that SSDs really rock, and seek times of ~0 do wonders for<br />the link step.<br /><br />That said, I was proud of my new hardware, until I read that. :/<br /><br />><br />><br />><br />> Anyway - the recipe doesn't have to be perfected for me to use it - and I<br />> suspect it's similar to OpenWRT's build, so maybe pointing me to the best<br />> help for that and what the differences are would be great.<br /><br />From a basic perspective, you have additional feeds in feeds.conf,<br />a specialized config, a special filesystem that does a few different<br />things - notably changing the device naming so you can have multiple<br />routed interfaces and simplified firewall rules -<br /><br />So you start by checking out cerofiles. The build_cero.sh script there<br />is obsolete but can supply clue as to the repos required and ketan had<br />some patches to that.<br /><br />What I do nowadays is mildly different than the script, in that after<br />the repos are pulled down, feeds.conf is configured, scripts/env new<br />whatever has been run and cerofiles imported into it, I tend to hammer<br />at it with<br /><br />./scripts/feeds install -p cero `cat env/override.list`<br />./scripts/feeds install `cat env/packages.list`<br />./scripts/feeds install -p cero `cat env/override.list`<br /><br />cp env/config-* .config<br />make defconfig<br />grep =m .config | sort -u > t1.txt<br />grep =m env/config* | sort -u > t2.txt<br /><br />diff t1.txt t2.txt<br /><br />add the packages via feeds install (I'm always adding new ones)<br /><br />the script ALMOST does all that.<br /><br /><br />(or I can can get it going for you in 10 minutes)<br /><br />><br />><br />><br />> I promise I will write the "port" experience up and post it on the Wiki, in<br />> case others want to port cerowrt to other "OpenWRT platforms" of sufficient<br />> capabilities.<br />><br />><br />><br />> David<br />><br />><br />><br />> -----Original Message-----<br />> From: "Outback Dingo" <outbackdingo@gmail.com><br />> Sent: Sunday, April 29, 2012 9:42pm<br />> To: "Dave Taht" <dave.taht@gmail.com><br />> Cc: cerowrt-devel@lists.bufferbloat.net<br />> Subject: Re: [Cerowrt-devel] speeding up builds<br />><br />> On Sun, Apr 29, 2012 at 8:15 PM, Dave Taht <dave.taht@gmail.com> wrote:<br />>> I finally acquired a machine with 32GB of ram, an intel 3930k (6<br />>> cores), and an SSD.<br />>><br />>> I put the build_dir, /tmp and /var/tmp on ramdisks, and...<br />>><br />>> This cut a complete cerowrt build (including toolchain) down from ><br />>> 3.5 hrs down to under 45 minutes.<br />>><br />>> Without the toolchain rebuild, but after a make clean (to rebuild the<br />>> packages and kernel), it's about 28 minutes.<br />>><br />>> I can see that it is possible to parallelize things more to maybe chop<br />>> another 30% of of things...<br />>> ...but I'm glad to have 3 hrs of my life back, per build.<br />>><br />>> I wanted to figure out to what extent modern hardware would enhance<br />>> the existing buildbot system.<br />>> Now I know...<br />><br />> odd my laptop will do a full build with tool chain in about an<br />> hour..... its only a core i3 with 6gb and an ssd<br />><br />>><br />>><br />>> --<br />>> Dave Täht<br />>> SKYPE: davetaht<br />>> US Tel: 1-239-829-5608<br />>> http://www.bufferbloat.net<br />>> _______________________________________________<br />>> Cerowrt-devel mailing list<br />>> Cerowrt-devel@lists.bufferbloat.net<br />>> https://lists.bufferbloat.net/listinfo/cerowrt-devel<br />> _______________________________________________<br />> Cerowrt-devel mailing list<br />> Cerowrt-devel@lists.bufferbloat.net<br />> https://lists.bufferbloat.net/listinfo/cerowrt-devel<br /><br /><br /><br />-- <br />Dave Täht<br />SKYPE: davetaht<br />US Tel: 1-239-829-5608<br />http://www.bufferbloat.net</p>
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