[molpro-user] Question about Memory usage

Kirk Peterson kipeters at wsu.edu
Wed Mar 25 15:35:06 GMT 2009


actually some further email exchanges with the original poster showed  
that the origin of the problem
seemed to be in his build of Molpro - top showed very large resident  
memory sizes of each molpro
image (much larger than what was requested).  Evidently the  
precompiled binary did not behave this


On Mar 25, 2009, at 12:26 AM, Ulrich Wedig wrote:

> I'm not an expert in operating systems, but my observation (and the
> interpretation) is the following. My Linux system (SuSE Linux ES) uses
> available free physical memory as a cache for I/O. The amount is given
> in the output of the top command as 'cached'. In many of my molpro  
> runs
> I observe, that the memory allocated for the processes and 'cache'
> (several GB) fill up the entire physical memory.
> In the version 9 of SLES there was obviously a bug in this caching
> mechanism. Physical memory was not freed appropriately when more  
> memory
> for processes was required. So, more and more swap space was used, and
> the processes were slowed down due to swapping. This bug is  
> corrected in
> version 10 of SLES.
> Ulrich Wedig
> Kirk Peterson wrote:
>> The one caveat is that the memory you specify in the input file is a
>> per process memory.  So if you run Molpro 4-way parallel the total
>> amount
>> of memory would be 256MB x 4 = 1GB in your case.  Even with that,
>> though, I'm not sure why your job used all of your available memory.
>> The residence
>> size of the executable is not all that big.  Can you do a "top" while
>> molpro is running to confirm that it is the process taking so much
>> memory?
>> -Kirk
>> On Mar 23, 2009, at 7:58 AM, zhendong zhao wrote:
>>> Dear Molpro users,
>>> I successfully compiled molpro 2008.1. Then I run bench tests on a  
>>> box
>>> with Intel CPU Q6600 and 4GB memory.
>>> I try to run this job, bench/mpp_big_direct_lmp2.com using 4 cores,
>>> the
>>> job consumed 4GB memory and filled the swap partition, so the
>>> calculation is terribly slow. If molpro uses 2 cores, the speed is
>>> fine, because it never use swap. My question is, the input file only
>>> requests "memory,32,m", 32mw in 64bit OS is 32x8MB = 256MB, why the
>>> job
>>> demands so many memory, how does molpro use memory?
>>> Thanks in advance.
>>> ZZ
>>> _______________________________________________
>>> Molpro-user mailing list
>>> Molpro-user at molpro.net
>>> http://www.molpro.net/mailman/listinfo/molpro-user
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> -- 
> -----------------------------------------------------------------
> Dr. Ulrich Wedig                              Tel. 0711/6891535
> Max-Planck-Institut fuer Festkoerperforschung FAX  0711/6891502
> Heisenbergstr. 1
> 70569 Stuttgart                               U.Wedig at fkf.mpg.de
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