Elapsed Wall Clock Time

JuPa · February 12, 2014, 05:22

Hi,

Is there a way to tell CFX to stop the simulation after 11 hours of wall clock run time? I submit jobs to a high end computer node, which the maximum allowed run time is 12 hours. Before the computer kicks me out and aborts my job I want to write a results file at the 11th hour.

I thought the "Elapsed Wall Clock Time Control" option might have done this but after reading the CFX Pre guide it seems I'm wrong.

I did a search, and read a comment by ghorrocks in this thread who said

Quote:

Originally Posted by ghorrocks

Another thing to consider - you can use the cfx5stop command to stop a run in progress. It will shut down the slover and write a complete results file of whereever it got to. If you want to be clever you can set up a timed job (maybe using cron) to execute cfx5stop just before your time is up. Make sure you give it enough time to complete the timestep it is working on and write the results file.

This sounds like what I want. Does anyone know of a way to implement this?

Thank you

flotus1 · February 12, 2014, 05:28

I had the same problem a few years ago and as far as I remember, the elapsed wall clock time control was exactly what I needed.

Lance · February 12, 2014, 05:35

I've had problems getting the elapsed wall clock time control to work, especially if Im using many cores for the simulation. It seems that it never kicks in, even though the wall clock time has expired. If I have to stop a simulation, I just run cfx5stop manually. Im sure there are ways to do it more efficiently, e.g. using cron as mentioned by Glenn.

ghorrocks · February 12, 2014, 05:37

The elapsed wall clock time is a new(ish) feature which makes it very easy. The alternative using a cron job is the old way of doing it - but the idea of running cfx5stop to stop a job is also useful with other triggers which are not built into CFX.

As for how to use cron: http://www.lmgtfy.com/?q=cron (sorry about the sarcasm but I have been itching to use that link

)

JuPa · February 12, 2014, 06:02

Excellent. Thanks for your replies. I'll do a bit more digging around using cron, and I'll run a few simple jobs using the command to see if it works.

P.S - Lance. I agree. I've had no luck getting the lapsed wall clock time control to work on 16 cores. I doubt it'll work when I ratchet up the power to 64 or 128 cores!

Lance · February 12, 2014, 06:57

Quote:

Originally Posted by RicochetJ

P.S - Lance. I agree. I've had no luck getting the lapsed wall clock time control to work on 16 cores. I doubt it'll work when I ratchet up the power to 64 or 128 cores!

If I remember correctly I got the control to work using 64 cores, but there was no way that it worked for 128 or more. However, cfx5stop worked fine for the same simulation. I asked Ansys about this a long time ago, but they never addressed the issue.

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February 12, 2014, 05:28		#2
flotus1 Super Moderator Alex Join Date: Jun 2012 Location: Germany Posts: 3,399 Rep Power: 46	I had the same problem a few years ago and as far as I remember, the elapsed wall clock time control was exactly what I needed.

February 12, 2014, 05:35		#3
Lance Senior Member Lance Join Date: Mar 2009 Posts: 669 Rep Power: 22	I've had problems getting the elapsed wall clock time control to work, especially if Im using many cores for the simulation. It seems that it never kicks in, even though the wall clock time has expired. If I have to stop a simulation, I just run cfx5stop manually. Im sure there are ways to do it more efficiently, e.g. using cron as mentioned by Glenn.

February 12, 2014, 05:37		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	The elapsed wall clock time is a new(ish) feature which makes it very easy. The alternative using a cron job is the old way of doing it - but the idea of running cfx5stop to stop a job is also useful with other triggers which are not built into CFX. As for how to use cron: http://www.lmgtfy.com/?q=cron (sorry about the sarcasm but I have been itching to use that link )

February 12, 2014, 06:02		#5
JuPa Senior Member Mr CFD Join Date: Jun 2012 Location: Britain Posts: 361 Rep Power: 14	Excellent. Thanks for your replies. I'll do a bit more digging around using cron, and I'll run a few simple jobs using the command to see if it works. P.S - Lance. I agree. I've had no luck getting the lapsed wall clock time control to work on 16 cores. I doubt it'll work when I ratchet up the power to 64 or 128 cores!