[Wien] [Extern] Re: RAM issues in lapw1 -bands

Peter Blaha pblaha at theochem.tuwien.ac.at
Thu Nov 29 14:16:50 CET 2018


This problem is easily solvable (it again means: You MUST READ the UG 
(parallelization), otherwise you will run VERY badly).

For such a small problem (14 atoms, matrixsize 2600)  it is NOT 
necessary (in fact probably even quite bad) to use mpi-parallelization.


Instead use k-parallelization (and maybe   export OMP_NUM_THREAD=2).

simply put eg. 24 lines like:

1:localhost

into the .machines file, and you will run 24 parallel lapw1 (each using 
2 cores when OMP_NUM_THREAD=2 is set).

--------------
With respect to your other questions:
I don't know what:  lapw1para_mpi -p -band is ??

lapw1 should be always invoked using:

x lapw1 -p      or    x lapw1 -p -band

The difference is just that you are using either case.klist or 
case.klist_band. Checkout how many k-points are in these 2 files (250 
was just an "input", it seems to have made a 13x13x1 mesh and then still 
applied symmetry, so you may have just ~ 30 k-points in case.klist ...)

-----------------
Another question: do you have 48 "physical cores", or only 24 ???
Do you have 2 or 4 Xeons (with 12 cores each) in your computer ??

If you have only 24 "real" cores:
The "virtual cores" which Intel gives you "for free" due to their 
"hyperthreading", are usually not very effective. You can at most expect 
an improvement of 10-20% when using 48 instead of 24 cores, but 
sometimes, this can also degrade performance by 30% because the 
memorybus gets overloaded. So test it ....



On 11/29/18 1:10 PM, Coriolan TIUSAN wrote:
> Thanks for the suggestion of dividing the band calculation.
> 
> Actually, I would like to make a 'zoom' around the Gamma point (for 
> X-G-X direction) with a resolution of about 0.001 Bohr-1 (to get enough 
> accuracy for small Rasba splittings, k_0< 0.01 Bohr-1). I guess I could 
> simply make the 'zoom' calculation?
> 
> The .machines, file, having in view that I have only one node (computer) 
> with 48 available CPUs is:
> 
> -------------------------------------
> 
> 1:localhost:48
> granularity:1
> extrafine:1
> lapw0:localhost:48
> dstart:localhost:48
> nlvdw:localhost:48
> 
> --------------------------------------
> 
> For a supercell here attached, I was trying to make a bandstructure 
> calculations along the X-G-X direction with at least 200 points....which 
> corresponds to a step of only 0.005 Bohr-1, not enough for Rashba in 
> same order of magnitude.
> 
> For my calculations I get: MATRIX SIZE  2606LOs: 138  RKM= 6.99 and the 
> RAM of 64Gk is 100% filles plus about 100G of swap...
> 
> Beyond all aspects, what I would like to understand is also why in scf 
> calculation I have no memory 'overload'  FOR 250K POINTS (13 13 1)... 
> while when running  'lapw1para_mpi -p -band ' the memory issue seem more 
> dramatic?
> 
> If necessary, my struct file is:
> 
> ------------------
> 
> VFeMgO-vid                               s-o calc. M||  1.00 0.00  0.00
> P 14
> RELA
>    5.725872  5.725872 61.131153 90.000000 90.000000 90.000000
> ATOM  -1: X=0.50000000 Y=0.50000000 Z=0.01215444
>            MULT= 1          ISPLIT= 8
> V 1        NPT=  781  R0=.000050000 RMT=   2.18000   Z: 23.00000
> LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
>                       0.0000000 1.0000000 0.0000000
>                       0.0000000 0.0000000 1.0000000
> ATOM  -2: X=0.00000000 Y=0.00000000 Z=0.05174176
>            MULT= 1          ISPLIT= 8
> V 2        NPT=  781  R0=.000050000 RMT=   2.18000   Z: 23.00000
> LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
>                       0.0000000 1.0000000 0.0000000
>                       0.0000000 0.0000000 1.0000000
> ATOM  -3: X=0.50000000 Y=0.50000000 Z=0.09885823
>            MULT= 1          ISPLIT= 8
> V 3        NPT=  781  R0=.000050000 RMT=   2.18000   Z: 23.00000
> LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
>                       0.0000000 1.0000000 0.0000000
>                       0.0000000 0.0000000 1.0000000
> ATOM  -4: X=0.00000000 Y=0.00000000 Z=0.13971867
>            MULT= 1          ISPLIT= 8
> Fe1        NPT=  781  R0=.000050000 RMT=   1.95000   Z: 26.00000
> LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
>                       0.0000000 1.0000000 0.0000000
>                       0.0000000 0.0000000 1.0000000
> ATOM  -5: X=0.50000000 Y=0.50000000 Z=0.18164479
>            MULT= 1          ISPLIT= 8
> Fe2        NPT=  781  R0=.000050000 RMT=   1.95000   Z: 26.00000
> LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
>                       0.0000000 1.0000000 0.0000000
>                       0.0000000 0.0000000 1.0000000
> ATOM  -6: X=0.00000000 Y=0.00000000 Z=0.22284885
>            MULT= 1          ISPLIT= 8
> Fe3        NPT=  781  R0=.000050000 RMT=   1.95000   Z: 26.00000
> LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
>                       0.0000000 1.0000000 0.0000000
>                       0.0000000 0.0000000 1.0000000
> ATOM  -7: X=0.50000000 Y=0.50000000 Z=0.26533335
>            MULT= 1          ISPLIT= 8
> Fe4        NPT=  781  R0=.000050000 RMT=   1.95000   Z: 26.00000
> LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
>                       0.0000000 1.0000000 0.0000000
>                       0.0000000 0.0000000 1.0000000
> ATOM  -8: X=0.00000000 Y=0.00000000 Z=0.30245527
>            MULT= 1          ISPLIT= 8
> Fe5        NPT=  781  R0=.000050000 RMT=   1.95000   Z: 26.00000
> LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
>                       0.0000000 1.0000000 0.0000000
>                       0.0000000 0.0000000 1.0000000
> ATOM  -9: X=0.00000000 Y=0.00000000 Z=0.36627712
>            MULT= 1          ISPLIT= 8
> O 1        NPT=  781  R0=.000100000 RMT=   1.68000   Z: 8.00000
> LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
>                       0.0000000 1.0000000 0.0000000
>                       0.0000000 0.0000000 1.0000000
> ATOM -10: X=0.50000000 Y=0.50000000 Z=0.36416415
>            MULT= 1          ISPLIT= 8
> Mg1        NPT=  781  R0=.000100000 RMT=   1.87000   Z: 12.00000
> LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
>                       0.0000000 1.0000000 0.0000000
>                       0.0000000 0.0000000 1.0000000
> ATOM -11: X=0.50000000 Y=0.50000000 Z=0.43034285
>            MULT= 1          ISPLIT= 8
> O 2        NPT=  781  R0=.000100000 RMT=   1.68000   Z: 8.00000
> LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
>                       0.0000000 1.0000000 0.0000000
>                       0.0000000 0.0000000 1.0000000
> ATOM -12: X=0.00000000 Y=0.00000000 Z=0.43127365
>            MULT= 1          ISPLIT= 8
> Mg2        NPT=  781  R0=.000100000 RMT=   1.87000   Z: 12.00000
> LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
>                       0.0000000 1.0000000 0.0000000
>                       0.0000000 0.0000000 1.0000000
> ATOM -13: X=0.00000000 Y=0.00000000 Z=0.49684798
>            MULT= 1          ISPLIT= 8
> O 3        NPT=  781  R0=.000100000 RMT=   1.68000   Z: 8.00000
> LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
>                       0.0000000 1.0000000 0.0000000
>                       0.0000000 0.0000000 1.0000000
> ATOM -14: X=0.50000000 Y=0.50000000 Z=0.49541730
>            MULT= 1          ISPLIT= 8
> Mg3        NPT=  781  R0=.000100000 RMT=   1.87000   Z: 12.00000
> LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
>                       0.0000000 1.0000000 0.0000000
>                       0.0000000 0.0000000 1.0000000
>     4      NUMBER OF SYMMETRY OPERATIONS
> -1 0 0 0.00000000
>   0 1 0 0.00000000
>   0 0 1 0.00000000
>         1   A   1 so. oper.  type  orig. index
>   1 0 0 0.00000000
>   0 1 0 0.00000000
>   0 0 1 0.00000000
>         2   A   2
> -1 0 0 0.00000000
>   0-1 0 0.00000000
>   0 0 1 0.00000000
>         3   B   3
>   1 0 0 0.00000000
>   0-1 0 0.00000000
>   0 0 1 0.00000000
>         4   B   4
> ---------------------------
> 
> 
> La 29/11/2018 13:05, Peter Blaha a scris:
>> You never listed your .machines file, nor do we know how many k-points 
>> are in the scf and the bandstructure cases and what the matrix 
>> size(:RKM)/ real/ complex details are.
>>
>> The memory leakage of intels mpi seems to be very version dependent, 
>> but there's nothing we can do against from the wien2k side.
>>
>> Besides installing a different mpi version, one could more easily run 
>> the bandstructure in pieces. Simply divide your klist_band file into 
>> several pieces and calculate one after the other.
>>
>> The resulting case.outputso_1,2,3.. files can simply be concatenated 
>> (cat file1 file2 file3 > file) together.
>>
>>
>>
>> On 11/28/18 1:41 PM, Coriolan TIUSAN wrote:
>>> Dear wien2k users,
>>>
>>> I am running wien 18.2 on Ubuntu 18.04 , installed on a HP station: 
>>> 64GB,  Intel® Xeon(R) Gold 5118 CPU @ 2.30GHz × 48.
>>>
>>> The fortran compiler/math library are ifc and intel mkl library. For 
>>> parallel execution I have MPI+SCALAPACK, FFTW.
>>>
>>> For parallel execution  (-p options +.machines), I have dimensioned 
>>> NMATMAX/NUME according to user guide. Therefore, standard 
>>> calculations in SCF loops turn well, without any memory paging 
>>> issues, about 90% of physical RAM being used.
>>>
>>> However, in supercells, once getting case.vector files,  when 
>>> calculating bands (lapw1c -bands  -p) with fine k structure (e.g. 
>>> above 150-200k on line X-G-X), necessary because I am looking to 
>>> small Rashba shifts at metel-insulator interfaces...all available 
>>> physical memory plus a huge amount of swap (>100G) are filled/used...
>>>
>>> Any suggestion/ideea for overcoming this issue...without adding 
>>> additional RAM?
>>>
>>> Why in lapw1 -p for selfonsistance memory looks enough while with 
>>> switch -band overload memory?
>>>
>>> With thanks in advance,
>>>
>>> C. Tiusan
>>>
>>>
>>>
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>>

-- 

                                       P.Blaha
--------------------------------------------------------------------------
Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-165300             FAX: +43-1-58801-165982
Email: blaha at theochem.tuwien.ac.at    WIEN2k: http://www.wien2k.at
WWW:   http://www.imc.tuwien.ac.at/TC_Blaha
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