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Re: The question about the memory usage of Firefly

Gena
alchemicylide@gmail.com


Dear Haichao,

I think there is enough memory in your system for this job. The problem is a typo in your input:

$SYSTEN NWORDS=500 $END

Firefly told you that 20 mwords wasn't enough, and this is a default value. You should use the following line instead:

$SYSTEM MWORDS=75 $END

This should be optimal and fits in your physical memory (if parallel job on 4 cores is used). Also, this is not very wise to set mwords value larger than the number of physical memory divided on the number of parallel threads to be used (the mwords value gives the memory dedicated to one thread of parallel job), because regression due to swapping will be great, unless your physical memory is really less than sufficient minimum.

Hope this could help.

Best,
Gena

On Fri Jan 13 '12 9:30am, Gilbert_Guo wrote
-------------------------------------------
>Hi, everyone.
>A question about the memory usage of Firefly confuses me, recently.  
>I did a calculations using Firefly 8.0 beta, attached please find the input file of this calculation. However, when I run it, the Firefly shows the information as follow:
>----------------------------------------------------------------------------------------------
> ADDING 30145072 WORDS MAY IMPROVE EFFICIENCY SIGNIFICANTLY!
>***** ERROR: MEMORY REQUEST EXCEEDS MAXIMUM.
>    45631552 WORDS REQUIRED     20000000 AVAILABLE.

>                         TIMING STATISTICS ON NODE 0:
> CPU        TIME:   STEP =      0.00 ,  TOTAL =     30.7 SECONDS (    0.5 MIN)
> WALL CLOCK TIME:   STEP =      0.00 ,  TOTAL =     30.6 SECONDS (    0.5 MIN)
> CPU UTILIZATION:   STEP =      0.00° TOTAL =     100.33SCP>    14848362 WORDS OF    DYNAMIC MEMORY USED
>----------------------------------------------------------------------------------------------
>The information of my computer is listed below:
>----------------------------------------------------------------------------------------------
>CPU: Intel Core 2 Quad 8400 2.33GHz, 4 Cores
>Mem: 4 GB+4 GB Swap
>System Info: Fedora 10 64 bit
>HardDisk: 500 GB (more than 400 GB free space)
>----------------------------------------------------------------------------------------------
>I know the physical memory may not enough, but I still wanna finish this calculation without adding memory. I wonder whether the Firefly could run an expensive task by reducing the efficiency/speed. If possible, how to do it?
>Thanks very much.

>Haichao Guo


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