Firefly and PC GAMESS-related discussion club


 
Learn how to ask questions correctly  
 
 
We are NATO-free zone
 



Re^3: Help needed regarding "asynchronous file I/O","Real time data packing" etc. to boost computational speeds.

Alex Granovsky
gran@classic.chem.msu.su


Dear Siddheshwar,

Just in case, you need to disable direct scf as well:

$scf dirscf=.f. $end

Kind regards,
Alex Granovsky



On Mon May 5 '14 7:57am, Siddheshwar Chopra wrote
-------------------------------------------------
>Dear Alex,
>I will try out the options provided by you. Thanks for the information.

>On Mon May 5 '14 2:49am, Alex Granovsky wrote
>---------------------------------------------
>>Dear Siddheshwar,

>>Most likely you did not see any effect due to async I/O and real time
>>file packing (i.e. compression) because you are running direct jobs.

>>Try to run large conventional (i.e. disk based) HF job. First, set:

>>

 $system async=0 $end
 $intgrl packao=.f. $end

>>then

>>

 $system async=1 $end
 $intgrl packao=.f. $end

>>then

>>

 $system async=0 $end
 $intgrl packao=.t. $end

>>then

>>

 $system async=1 $end
 $intgrl packao=.t. $end

>>Save outputs, compare execution times, and compare size of "aoints" files.

>>>In the manual it says that asynchronous file I/O is by default OFF in Linux.. Why so? and why is it ON for Windows?

>>Asynchronous file I/O is off under Linux by default mainly due to
>>compatibility problems with old buggy Linuxes. Presently, it is safe
>>to use this option under Linux.

>>It is turned on under Windows by default because there were not any
>>compatibility problems reported so far and because the performance
>>gain due to its use is more significant under Windows OS.  

>>> Does option "ASYNC=2" seem better?

>>There is only a subtle difference between ASYNC=2 and ASYNC=1

>>>What is Realtime data packing and how to control it?

>>The real time data packing (real time data compression) uses very fast
>>and efficient data compression methods in order to compress data
>>before storing them on the disk and decompress them back when reading
>>them from disk. See:

>>http://classic.chem.msu.su/gran/gamess/packing.htmlhttp://classic.chem.msu.su/gran/gamess/packing.htmlhttp://classic.chem.msu.su/gran/gamess/packing.htmlhttp://classic.chem.msu.su/gran/gamess/packing.html

>>and

>>http://classic.chem.msu.su/gran/gamess/Firefly_input_rev002.pdfhttp://classic.chem.msu.su/gran/gamess/Firefly_input_rev002.pdfhttp://classic.chem.msu.su/gran/gamess/Firefly_input_rev002.pdfhttp://classic.chem.msu.su/gran/gamess/Firefly_input_rev002.pdf

>>(search for PACKAO, FASTCI, and PACK2 keywords).

>>Hope this helps.

>>Kind regards,
>>Alex Granovsky
>>
>>
>>
>>On Tue Apr 29 '14 8:18am, Siddheshwar Chopra wrote
>>--------------------------------------------------
>>>Dear Firefly users,
>>>I would be grateful if anyone could explain the use of "asynchronous file I/O","Real time data packing" and Dynamic load balancing, to boost the computation speeds. Actually I went through a ppt about Firefly where all these features when switched on, resulted in very high speeds (for a fullerene dimer). DLB seems okay to me, but others are not.
>>>In the manual it says that asynchronous file I/O is by default OFF in Linux.. Why so? and why is it ON for Windows? Does option "ASYNC=2" seem better?
>>>What is Realtime data packing and how to control it?

>>>Thanks in advance,

>>>Kind Regards,


[ Previous ] [ Next ] [ Index ]           Tue May 6 '14 6:31am
[ Reply ] [ Edit ] [ Delete ]           This message read 527 times