On Thu, Apr 13, 2017 at 12:54 PM, Ian Hinder <[email protected]> wrote:

>
> On 13 Apr 2017, at 17:14, David Gore <[email protected]> wrote:
> ... When you build with "sim build", if you are on a known machine,
> simfactory automatically selects an optionlist appropriate for that
> machine.  Otherwise, you can specify an optionlist with --optionlist
> <name>, where the name should be an optionlist in
> simfactory/mdb/optionlists.  You may also be able to pass a path to an
> optionlist, I'm not sure.  This optionlist is then copied into
> configs/<configname>/OptionList, and Cactus starts to build.  As part of
> the cactus build process, the file make.config.defn is generated containing
> various settings based on what was in the optionlist.  I consider this to
> be an auto-generated file, and not one that should be edited by hand.  You
> should be able to achieve everything you need by editing the original
> optionlist.
>

This is good to know, but I assume that simply copying the make.config.defn
file to mymachine.mydomain.edu in /mdb/optionlists will probably not work.
Is there a preferred way to know how to populate the optionlist?


> One gotcha is that if you do modify the optionlist in
> simfactory/mdb/optionlists, the next Cactus build will NOT use this updated
> file unless you explicitly pass the --optionlist <optionlist> argument to
> sim build.
>

> You didn't actually say in your email how you are building Cactus.  Are
> you building using simfactory, i.e. "sim build", or with the Cactus make
> system (which is what simfactory calls), i.e. "make sim-config"?
>
>
What instructions are you following for building?
>

I am compiling via ./simfactory/bin/sim build [--clean]
--thornlist=manifest/einsteintoolkit.th
But you say that even if I create a mymachine.mydomain.edu optionlist, when
I recompile, I will need to add "--optionlist=mymachine.mydomain.edu" to
that build line?

To be fair, I *was* kinda hoping that the build would be similar to
WaveToyDemo.  But when I first started by building on my debian laptop, I
followed the instructions I found here:
https://docs.einsteintoolkit.org/et-docs/Simplified_Tutorial_for_New_Users

So I stuck with the altered build method.

> Neither of the config.logs under configs/sim/config-data or under
> configs/sim/scratch/hwloc/hwloc-1.10.1 had anything useful except for the
> compile line.  But this is because, when "-openmp" was passed to gcc, it
> made an executable named "penmp" which the configure script wasn't looking
> for.  So there was no actual compilation error---it just couldn't find the
> resulting binary.  That made this harder to diagnose.
>
>
> Interesting.  The error message surely must have gone somewhere though!
> It should have complained that it couldn't find a binary of the given name.
>

It simply said that the compiler doesn't produce executables.  I'm guessing
it was looking for a.out.


> Aha - I was the one who wrote that page, so this is my fault.  What is
> meant here is that machine ~= cluster, and node ~= compute node, which
> would indeed have a 1:1 mapping with a motherboard, and the motherboard may
> contain several CPUs (corresponding to "sockets"), and each CPU will
> contain multiple cores.
>

Ok, so for a *single* computer, machine = node.  I don't have such grand
designs as running on a cluster.  Yet.  :-)

>
> It seems to me that faster code would occupy more cores (one process per
> core), not more threads/process.  But it looks like I'll be wandering down
> to our CS department to clean up "process," "thread," and "hyperthread" :-)
>
>
> That's going a bit far :) You could also try:
>
> https://en.wikipedia.org/wiki/Process_(computing)
> https://en.wikipedia.org/wiki/Thread_(computing)
>

Too late.  I almost didn't get to my class on time after poking the bears
in our CS department. :-)  I'm a little more educated, but it still seems
that---although there are caveats---one process per core is usually the
faster option.


>
> I wouldn't worry about hyperthread for now.
>

Vielen Dank.  ;-)


>
> --
> Ian Hinder
> http://members.aei.mpg.de/ianhin
>
>


-- 
David Gore, Ph.D., Lecturer in Physics
Department of Physics, Computer Science and Engineering
Christopher Newport University
Office: 309 Luter Hall
Voice: 757 594 7827 <%28757%29%20594-7827>
_______________________________________________
Users mailing list
[email protected]
http://cactuscode.org/mailman/listinfo/users

Reply via email to