[Carpet] checkpoint at run-time request

[Erik Schnetter]

On Oct 18, 2006, at 09:15:59, Bela Szilagyi wrote:

> Every once in a while (e.g., five minutes ago) I find myself guilty  
> of not
> having requested checkpoint files at a large enough frequency.
>
> In other terms, my current run may die before getting to its first  
> check-point
> file.  It will check-point at termination, but this data may not be  
> good for
> restarting another run with a "fix".
>
> The question comes -- would it be possible to add some feature that  
> would
> allow me to tell a running simulation -- "please dump a checkpoint,  
> then go
> on."  The ordinary solution would be having Cactus watch a file in  
> which the
> user can place the request...  I know there is the web-interface  
> option of
> steering parameters, but I never trusted that enough to try...
>
> Could one just send a signal of some sort to the running code and  
> have the
> checkpoint file be dumped?
>
> More generically, it would be quite useful to have a simple,  
> usable, and
> trustworthy way of modifying parameters of a run, while it's  
> running.  Say,
> again, a simple ascii file being watched, read, parsed at every so  
> many
> iterations...

I forgot to mention: Thorn HTTPD can either run once per iteration,  
which leads to a rather slow user interface, or it can run in a  
parallel thread to the application.  For that you need to set  
PTHREADS=yes when you configure.

You activate thorn HTTPD with: ActiveThorns = "HTTPD HTTPDExtra Socket"

You can set a user name and password to allow only specific people to  
control your simulation.

You can look at an example at http://cactus.cct.lsu.edu:5555/.  User  
name and password for controlling are "anon" and "anon".

-erik

-- 
Erik Schnetter <schnetter at cct.lsu.edu>

My email is as private as my paper mail.  I therefore support encrypting
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