[Beowulf] Re: energy costs and poor grad students

Mark Kosmowski mark.kosmowski at gmail.com
Thu Jul 3 13:13:12 EDT 2008


> Prentice Bisbal wrote:
> > Mark Kosmowski wrote:
> >
> >
> >> I think I have come to a compromise that can keep me in business.
> >> Until I have a better understanding of the software and am ready for
> >> production runs, I'll stick to a small system that can be run on one
> >> node and leave the other two powered down.  I've also applied for an
> >> adjunt instructor position at a local college for some extra cash and
> >> good experience.  When I'm ready for production runs I can either just
> >> bite the bullet and pay the electricity bill or seek computer time
> >> elsewhere.
> >>
> >
> > Mark,
> >
> > For MPI testing/debugging, you can create a few virtual machine on one
> > node using VWware or Xen. VMWare is free, unless you want all the bells
> > and whistles.
> >
>
> You don't need to go this far. Just set up the hostfile to use the same
> host name several times. Just make sure you don't start swapping :)
>
> Jeff
>
My problem is RAM.  I'm using stable codes and not doing much
programming of my own, other than to tweak output formats to suit my
needs.

I've come up with some solutions.  First, I'll spend some time this
weekend moving files around and physically swapping DIMMs (I'm gonna
have sore thumbs again :( ) to get one machine with somewhere between
8 and 16 Gb.  After I do the file transferring I can then run just one
workstation with a big amount of RAM.  This amount of RAM should keep
me in business for even most of my production runs until I get to a
certain size of system to be studied.

Next, tomorrow I am going to install some laminate flooring for my
parents and will endeavor to extort a new laptop out of them - mine no
longer communicated to the LCD screen - tearing it apart to see what
is wrong was going to be my first unemployment project but the went
and extended my employment contract another 6 months.

Step three - time to upgrade the entertainment machine to a 64-bit
dual core system from the 32-bit ancient chip it has.  I'll try to get
this to 6 or 8 Gb RAM - then if needed I can use it as a half-node as
needed to supplement the workstation without firing up more machines.
This will leave two machines powered down and hopefully half the
computing power usage.

Maybe it would be a better idea to just buy more RAM for the two HDAMA
opteron systems and use one of those as a part-time entertainment /
vmware windows machine by just getting a PCI-X video card (I'm asking
on the OpenSUSE forum whether the HDAMA PCI-X slots will run a PCI-X
video card - feel free to comment on this here too).  I'll make a RAM
inventory this weekend and post the results.  If I can get one of
these systems to 12 - 16 Gb and the other to 8 - 12 Gb, this may be
the best choice.  Time to learn vmware and wine.

Right now, my CoW (cluster of workstations from RGB's book) uses the
oldest 64-bit machine as a "head node".  This machine is the slowest
and only has 4 DIMM slots, one of which I'm having difficulties with,
so this machine is definitely going down.  The other two nodes use an
HDAMA mother board, each with 8 DIMM slots - I have 2 Gb and 1 Gb
DIMMs on hand.  I'm thinking that perhaps the best thing to do is just
physically move the data drive to the machine slated to be a full-time
calculator (the one with the most RAM) and then fix paths as needed.

Someone suggested downclocking - would downclocking a step or two in
BIOS find a sweet spot as far as speed per energy unit similar to
driving in the 45 - 55 mile per hour range?

I hope no one is too upset I'm doing this planning on list.
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