[molpro-user] Question about Memory usage

[Kirk Peterson]

Ulrich,

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
way.

-Kirk

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
> -----------------------------------------------------------------
>