[petsc-users] performance issue solving multiple linear systems of the same size with the different preconditioning methods

[Алексей Рязанов]

I've figured out, that the amount of undestroyed objects depends on the type
of the linear system matrix. Now I'm assembling 3d laplacian with Neuman
boundary conditions, which is singular, and I have huge amount of
undestroyed vectors, mappings and scatters. If I use zero matrix, the number
of destroyed objects equals to the number of created. But if I even
use unitary matrix, which is not singular,I already have some undestroyed
objects.

27 августа 2011 г. 1:29 пользователь Алексей Рязанов <ram at ibrae.ac.ru>написал:

> I have also checked KSPSolve behavior in my other PETSc programs and found
> the same memory lack
>
> 27 августа 2011 г. 0:57 пользователь Алексей Рязанов <ram at ibrae.ac.ru>написал:
>
>
>> Thank you for your response!
>>
>> I have the memory leak in both my programs. But I don't create plenty of
>> vectors.
>>
>> My code looks like:
>>
>>   ***INIT_ALL***
>>   PetscLogStageRegister("Iteration  :", &StageNum1);
>>   PetscLogStagePush(StageNum1);
>>   KSPSolve(dKSP, dvec_origRHS, dvec_Solution);
>>   PetscLogStagePop();
>>   ***DESTROY_ALL***
>>
>>
>> And when I comment (or delete) KSPSolve, the log_summary output is:
>>
>> =====================================================
>> Memory usage is given in bytes:
>>
>> Creations   Destructions     Memory  Descendants' Mem Object Type
>>
>> Reports information only for process 0.
>>
>> --- Event Stage 0: Main Stage
>> 1              1         729472     0   Application Order
>> 1              1         225452     0   Distributed array
>> 8              8       1533424     0   Vec
>> 3              3             2604     0   Vec Scatter
>> 8              8         613852     0   Index Set
>> 1              1         221304     0   IS L to G Mapping
>> 3              3     16603440     0   Matrix
>> 1              1               832     0   Krylov Solver
>> 1              1               688     0   Preconditioner
>> 1              1               448     0   PetscRandom
>>
>> --- Event Stage 1: Iteration  :
>> =====================================================
>>
>> When I run the code with KSPSolve instruction, it gives me:
>>
>> =====================================================
>> Memory usage is given in bytes:
>> Creations   Destructions     Memory  Descendants' Mem Object Type
>>
>> Reports information only for process 0.
>>
>> --- Event Stage 0: Main Stage
>> 1              0            0            0      Application Order
>> 1              0            0            0      Distributed array
>> 8             17      4963592     0      Vec
>> 3              2         1736         0      Vec Scatter
>> 8             12      1425932     0      Index Set
>> 1              0            0            0      IS L to G Mapping
>> 3              5     50158132     0      Matrix
>> 1              2         1664         0      Krylov Solver
>> 1              2         1440         0      Preconditioner
>> 1              1          448          0      PetscRandom
>> 0              1          544          0      Viewer
>>
>> --- Event Stage 1: Iteration  :
>> 355        173   64692312     0      Vec
>> 1              0            0            0      Vec Scatter
>> 6              2         1024         0      Index Set
>> 2              0            0            0      Matrix
>> 1              0            0            0      Krylov Solver
>> 1              0            0            0      Preconditioner
>> 2              1          544          0      Viewer
>> =====================================================
>>
>>
>>
>>
>> 2011/8/25 Jed Brown <jedbrown at mcs.anl.gov>
>>
>>> On Tue, Aug 23, 2011 at 02:37, Алексей Рязанов <ram at ibrae.ac.ru> wrote:
>>>
>>>> When i delete the 4-5-6 part of 2nd, 1-2-3 works great! with exact like
>>>> 1st results.
>>>> When i delete the 1-2-3 part of 2nd, 4-5-6 works great! with exact like
>>>> 1st results.
>>>> All program (1-2-3-4-5-6) works badly.
>>>>
>>>
>>> From the -log_summary, you have a memory leak (many more vector creations
>>> than destructions). Try running with -malloc_dump to debug it. Perhaps you
>>> are creating a vector every time one of your functions is called? You should
>>> also build --with-debugging=0 when looking at timing results. (You can keep
>>> it in PETSC_ARCH=linux-gnu-opt.)
>>>
>>
>>
>>
>> --
>> Best regards,
>> Alexey Ryazanov
>> ______________________________________
>> Nuclear Safety Institute of Russian Academy of Sciences
>>
>>
>>
>
>
> --
> Best regards,
> Alexey Ryazanov
> ______________________________________
> Nuclear Safety Institute of Russian Academy of Sciences
>
>
>


-- 
Best regards,
Alexey Ryazanov
______________________________________
Nuclear Safety Institute of Russian Academy of Sciences
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