[CPMD-list] NCACHE size

[Philippe Blaise]

Kozin, I (Igor) wrote:

>>I made some tests on my opteron machine, and cpmd link to atlas is 
>>approx. 1.5 more efficient than
>>cpmd link to acml, so that's right, with cpmd the first thing to do is 
>>to find an optimized blas/lapack lib
>>for your cpu, and then after you should play with the ncache value.
>>Many thanks to the guys who made atlas, (even if the mkl is more 
>>efficient with the itanium2 ).
>>    
>>
>
>The difference I see on our Opteron 244 (wat32 benchmark) is about 2%:
>Axel's pre-built Atlas for Opterons is slightly quicker than Gnu ACML 2.0.
>Does it mean Atlas _has_ to be locally tuned?
>
>  
>
Igor, you are right.I have down my tests some weeks ago with the acml 
libs bundled with PGI 5.1 and 5.2,
but with the last acml lib ver 2.1, the timings are similar to the ones 
obtained with the atlas lib provided
by Alex. AMD has done some efforts.
bye.
Phil.

>>>PB> >btw: the best way to optimize the fft is use it as little as 
>>>PB> >possible (e.g. by using the REAL SPACE WFN KEEP keyword, provided
>>>PB> >there is enough memory on your machine).
>>>      
>>>
>
>Apologies for diverting the topic further...
>Just tried REAL SPACE WFN KEEP and got 
>  MEMORY| MEMORY REQUIRED:   274776194  WORDS
> PROGRAM STOPS IN SUBROUTINE MEMORY| TOO BIG VALUE
>
>memory.F: 82-91
>#if !defined(MALLOC8)
>C     Check if 8 * LEN is in the range of integer.
>      IF(IRAT.EQ.2) THEN
>C       Integer=integer*4 : 2^31=2147483648, 2^28=268435456
>        IF(LEN.GT.2**28) THEN
>          WRITE(*,*) ' MEMORY| MEMORY REQUIRED:',LEN,' WORDS'
>          CALL STOPGM('MEMORY','TOO BIG VALUE')
>        ENDIF
>      ENDIF
>#endif
>
>As far as I can see I can do nothing about IRAT. Can I use MALLOC8?
>I remember Axel advised for POINTER8 but against using MALLOC8 a while
>ago...
>
>Igor
>
>  
>