CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   CD-adapco (http://www.cfd-online.com/Forums/cd-adapco/)
-   -   memory management under unix system (http://www.cfd-online.com/Forums/cd-adapco/54462-memory-management-under-unix-system.html)

nicolas March 21, 2005 05:57

memory management under unix system
 
Hi,

I have an important problem with management of memory under unix os (kernel : 2.4.18-6mdkenterprise). I would like to submit a job using 2 Go of ram. We have a quadriprocessor with 4 Go of ram. But the os seems to divide the total memory ressources by the number of processors (impossible to run a job exceeding 1 Go of ram). Can you give me some advice concerning modifications of our system os in order to allow large computation (without pro-hpc license).

Cordially yours.


Jörn Beilke March 21, 2005 10:17

Re: memory management under unix system
 
Either you switch to a 64bit platform or you run the case in parallel.

nicolas March 21, 2005 13:38

Re: memory management under unix system
 
There is no other way to allocate the total amount of memory to a single processor?

4xF March 22, 2005 05:36

Re: memory management under unix system
 
My guess is that this is set by kernel parameters, for which a given amount of mem is set per processor. Can you check that?

nicolas March 22, 2005 13:00

Re: memory management under unix system
 
High memory is activated, but submission of large simulation (executable of 2 Go) is still impossible (segmentation fault). Have you please some advice about kernel parameter in order to allow my computation ?

4xF March 22, 2005 13:58

Re: memory management under unix system
 
BTW, which version of the code are you using and with which kind of operating system? Is it by chance Linux and v3.150A?

nicolas March 22, 2005 14:04

Re: memory management under unix system
 
I used linux with release v3.150A. I hope that you have the solution or informations about configuration of pro hpc on multi proc linux server.

Thancks by advance

4xF March 22, 2005 14:32

Re: memory management under unix system
 
Then the reason is why you cannot run a simulation requiring more than 1 GB of memory comes from the dynamic linking of libraries. Solution: You need to compile a static executable with the additional compile option -Y, hence from the command line: star -Y -snf star-star.exe instead of the default options: star -svf star-star.exe

Note that star-star.exe is the default executable name. For getting all the starlink options => starlink -h

Enjoy... ;-)

nicolas March 23, 2005 05:43

Re: memory management under unix system
 
Always trouble with compilation. Y option do not appears in my compilator options (Absoft fortran 77 compiler 5.0). In your previous message you recommand to use : star -Y -snf star.exe star is not a valid command (you may be think to starlink ??).

Actually i'm looking to used prohpc, but i have some trouble with mpich environment setup but i keep faith ;)

Help is welcome :D

Jörn Beilke March 23, 2005 06:47

Re: memory management under unix system
 
Iy you want to use between 1GB and 2GB with your version you have to add the -Y switch when doing the starlink.

> starlink -Y .....


4xF March 23, 2005 09:50

Re: memory management under unix system
 
First, I apologize. You should have read starlink instead of star (that happens when you write it at late hours...). Anyway, for parallel runs, please install the mpich libraries the STAR-CD support office should have provided you with (latest version is 1.2.4 to my best knowledge). If they are already installed, check the environment variables MPI_ROOT, MPI_DEVICE and MPI_ARCH. Adding $MPI_ROOT/$MPI_ARCH/$MPI_DEVICE/bin to you $PATH should allow you to find mpirun. That's something to start with... For additional details, please read the installation guide...

Hope this helps you further.

ali April 5, 2005 03:16

Re: memory management under unix system
 
respected sir i m looking for hte detail of the topic according to the operating system point of view your positive action in this regard will be highly appriciated

omair aamir April 7, 2005 03:32

Re: memory management under unix system
 
i need the complete documentation and code if provided please consider my request thanking you

Gustav W April 21, 2005 08:51

Re: memory management under unix system
 
please send me the notes

tallat July 2, 2005 16:47

Re: memory management under unix system
 
i want details of this topic

kumar August 3, 2005 13:52

Re: memory management under unix system
 
mesg from mem.mang on unix

satheeshkumar October 7, 2005 07:30

Re: memory management under unix system *NM*
 

girish gaurav October 15, 2005 08:19

Re: memory management under unix system
 
plz send me the the a breif detail about memory management in unix system. i will be greatfull to you. girish gaurav


sarvani kalagara November 8, 2005 06:06

Re: memory management under unix system
 
sir, can u please send me this article u have written on unix memory mangement as i need it for my project work..

thanking you

sarvani k


iftikhar khan December 28, 2005 04:34

unix memory managment
 
send me notes


All times are GMT -4. The time now is 17:19.