[petsc-users] Performance of PETSc TS solver

[Jin, Shuangshuang]

Hi, Jed,

I followed your suggestion and profiled the IJacobian stage, please see the related profile below:

Summary of Stages:   ----- Time ------  ----- Flops -----  --- Messages ---  -- Message Lengths --  -- Reductions --
                        Avg     %Total     Avg     %Total   counts   %Total     Avg         %Total   counts   %Total
 0:      Main Stage: 4.0670e+01  11.5%  1.2019e+11 100.0%  1.082e+07 100.0%  5.757e+02      100.0%  6.386e+04  81.6%
 1: My IJacobian stage: 3.1379e+02  88.5%  0.0000e+00   0.0%  1.984e+03   0.0%  1.357e-02        0.0%  1.438e+04  18.4%

Event                Count      Time (sec)     Flops                             --- Global ---  --- Stage ---   Total
                   Max Ratio  Max     Ratio   Max  Ratio  Mess   Avg len Reduct  %T %f %M %L %R  %T %f %M %L %R Mflop/s
------------------------------------------------------------------------------------------------------------------------
--- Event Stage 1: My IJacobian stage

VecSet              1797 1.0 4.7467e-02 1.9 0.00e+00 0.0 0.0e+00 0.0e+00 0.0e+00  0  0  0  0  0   0  0  0  0  0     0
VecScatterBegin     1796 1.0 4.3967e-01 1.1 0.00e+00 0.0 0.0e+00 0.0e+00 1.8e+03  0  0  0  0  2   0  0  0  0 12     0
MatAssemblyBegin    1796 1.0 7.2787e+00 1.8 0.00e+00 0.0 0.0e+00 0.0e+00 3.6e+03  2  0  0  0  5   2  0  0  0 25     0
MatAssemblyEnd      1796 1.0 2.1605e-01 1.1 0.00e+00 0.0 2.0e+03 7.4e+01 1.8e+03  0  0  0  0  2   0  0100100 13     0

Object Type          Creations   Destructions     Memory  Descendants' Mem.
--- Event Stage 1: My IJacobian stage

              Vector  1798              1         1552     0
      Vector Scatter  1797           1796      1156624     0
           Index Set  1798           1798      1370952     0

It seems that IJacobian occupies 88.5% of the total computation time. Anything else can you interpret from the profile which can help me to accelerate the IJacobian computation?

Thanks,
Shuangshuang



-----Original Message-----
From: Jed Brown [mailto:five9a2 at gmail.com] On Behalf Of Jed Brown
Sent: Tuesday, August 13, 2013 6:50 PM
To: Jin, Shuangshuang; Shri
Cc: Barry Smith; petsc-users at mcs.anl.gov
Subject: RE: [petsc-users] Performance of PETSc TS solver

"Jin, Shuangshuang" <Shuangshuang.Jin at pnnl.gov> writes:

> Hi, Shri,
>
> From the log_summary, we can see that the TSJacobianEval/SNESJacobianEval dominates the computation time as you mentioned.
>
> Event                Count      Time (sec)     Fl
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