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FreeBSD Looking for People with Lots of RAM

Posted by CowboyNeal on from the not-just-for-ram-drives-anymore dept.

drdink writes "A few weeks ago, PAE (Physical Address Extension) support was added to FreeBSD 5-CURRENT. This allows memory above 4GB to be used normally by the kernel and userland on the x86 platform. Jake Burkholder, the man behind PAE, is now looking for users to help him test this new feature. In his message to the freebsd-current mailing list, Jake describes the current caveats to PAE and also says 'We'd like this feature to be solid for 5.1-RELEASE, so I'm hoping there are people out there with systems with more than 4G of ram that are willing to test it.' This, along with other features make FreeBSD 5-STABLE look very promising."

4 of 271 comments (clear)

  1. Volunteer... by addaon · · Score: 4, Interesting

    I have an HP LXR 8500 with four processors (currently) and 4GB of ram. I've been considering upgrading to 6GB for a while anyway. I'm currently using Windows 2000 advanced server on it, after being somewhat frustrated with Linux support a couple of years ago. I'd be more than willing to try out BSD, although I never have before. Is there anything I should know about this? I presume that BSD would run Mathematica fine under Linux emulation mode, as my main use of the box is just Mathematica crunching. Does FreeBSD make reasonable use of four processors? Anything else I should beware of? And anyone know a good source for cheap lxr-ready ram?

    --

    I've had this sig for three days.
    1. Re:Volunteer... by Brooks+Davis · · Score: 5, Interesting

      Mathematica runs find under Linux emulation. We're currently working on getting Grid Mathematica into production on our FreeBSD cluster at work. It runs, but we haven't really done much with it yet because the real users are still working on understanding the programming model. FreeBSD should work well for you in this mode as long as you have the four licenses you'll need to keep the CPUs busy. The way Mathematica handles parallelism (seperate processes) should be able to take advantage of PAE.

      The one gotcha is that PAE is a bit bleeding edge at this point so moving to it may be intresting.

      -- Brooks

      --
      -- Any statement of the form "X is the one, true Y" is FALSE.
    2. Re:Volunteer... by Billly+Gates · · Score: 4, Interesting

      Yes but its unbenchmarked

      FreeBSD 5 also includes Linux like threading. This has been one of the traditional weaknesses that are being addressed. Great java support as well. Since java uses threading heavily FreeBSD 5 will make it have server/workstation performance. Yahoo wanted to go with Java for their next generation portal software but Freebsd 4.x series had mediocre thread support.

      Freebsd 5.0 rocks! The only downside is that my Microsoft USB keyboard does not work with FreeBSD 5 on certain motherboards. I think its a bug and I hope its fixed soon.

      --
      http://saveie6.com/
    3. Re:Volunteer... by addaon · · Score: 4, Interesting

      Mathematica is slow, inefficient, and a total joy to work with. Matlab is about 10x faster, and at least 100x faster for matrix stuff (mathematica does matrices as linked lists of linked lists!)... but if I want speed, I'll use Fortran 90, really. Mathematica is just lisp + pretty printing... but it undeniably works, and I've never used a more productive tool in my life.

      My basic method is to take a 3D solid (that is, a polygonal 3D model that encloses a volume). I apply a few standard smoothing operations to this model to get a very, very rough shape (in particular, I smooth it until it is fully convex, the first time). I then do simulated annealing based on a handful of hardcoded starting conditions to find a good approximation of that shape -- metropolis might work better for precision, but I decidedly don't want precision now. I then take the model and resmooth it, but one step less. I use the previous foldset as a starting point, and anneal from there. I repeat this for each level of smoothing that was originally needed.

      Normally it takes around a million attempts to approximate each smoothing level, although this varies by a factor of at least one hundred, where the swan, for instance, takes about fifty levels of smoothing.

      Make sense? Not saying it works wonderfully, but I think it's the correct approach and just needs tuning. Amount of work is, to a first approximation, linear with the geometric complexity of the model, and more or less independent of the number of folds... certainly not exponential in the number of folds!

      --

      I've had this sig for three days.