[petsc-users] KSPSolve errors on blues

[Barry Smith]

> On Jun 8, 2016, at 1:30 PM, Xujun Zhao <xzhao99 at gmail.com> wrote:
> 
> A quick test of a smaller system on my laptop with 25x25x25 mesh gives the following info.
> The memory used keeps increasing from 1 to 3 CPUs, but slightly decreases with 4 CPUs.

   yes this does not look problematic

> On the other hand, 60x60x60 mesh (2.9M dofs) is also not a big system...

  True. 

   I think you need to run the 60 60 60 system also on 1 2 4 and 8 processes to see how the memory trends. I don't think we should eliminate memory as the culprit yet.


  Barry

> 
> 
> ------------------------------------------------- 1 CPU -------------------------------------------------
> Summary of Memory Usage in PETSc
> Maximum (over computational time) process memory:        total 4.7054e+09 max 4.7054e+09 min 4.7054e+09
> Current process memory:                                                     total 4.7054e+09 max 4.7054e+09 min 4.7054e+09
> Maximum (over computational time) space PetscMalloc()ed: total 1.6151e+09 max 1.6151e+09 min 1.6151e+09
> Current space PetscMalloc()ed:                                           total 7.7232e+04 max 7.7232e+04 min 7.7232e+04
> 
> ------------------------------------------------- 2 CPU -------------------------------------------------
> Summary of Memory Usage in PETSc
> Maximum (over computational time) process memory:        total 6.2389e+09 max 3.1275e+09 min 3.1113e+09
> Current process memory:                                                     total 6.2389e+09 max 3.1275e+09 min 3.1113e+09
> Maximum (over computational time) space PetscMalloc()ed: total 2.1589e+09 max 1.1193e+09 min 1.0397e+09
> Current space PetscMalloc()ed:                                           total 1.5446e+05 max 7.7232e+04 min 7.7232e+04
> 
> ------------------------------------------------- 3 CPU -------------------------------------------------
> Summary of Memory Usage in PETSc
> Maximum (over computational time) process memory:        total 7.7116e+09 max 1.9572e+09 min 1.8715e+09
> Current process memory:                                                     total 7.7116e+09 max 1.9572e+09 min 1.8715e+09
> Maximum (over computational time) space PetscMalloc()ed: total 2.1754e+09 max 5.8450e+08 min 5.0516e+08
> Current space PetscMalloc()ed:                                           total 3.0893e+05 max 7.7232e+04 min 7.7232e+04
> 
> ------------------------------------------------- 4 CPU -------------------------------------------------
> Summary of Memory Usage in PETSc
> Maximum (over computational time) process memory:        total 7.1188e+09 max 2.4651e+09 min 2.2909e+09
> Current process memory:                                                     total 7.1188e+09 max 2.4651e+09 min 2.2909e+09
> Maximum (over computational time) space PetscMalloc()ed: total 2.1750e+09 max 7.6982e+08 min 6.5289e+08
> Current space PetscMalloc()ed:                                           total 2.3170e+05 max 7.7232e+04 min 7.7232e+04
> 
> 
> On Wed, Jun 8, 2016 at 11:51 AM, Barry Smith <bsmith at mcs.anl.gov> wrote:
> 
>    Signal 9 SIGKILL on batch systems usually means the process was killed because it ran out of time or ran out of memory.
> 
>     Perhaps there is something in the code that is unscalable and requires more more memory with more processes. You can run on 1 2 and 3 processes and measure the memory usage to see if it goes up with the number of processes using for example -memory_view
> 
>   Barry
> 
> 
> 
> > On Jun 8, 2016, at 11:41 AM, Xujun Zhao <xzhao99 at gmail.com> wrote:
> >
> > Hi all,
> >
> > I am running a FE Stokes Solver with schur complement type PC on blues. The program runs well when mesh is 40X40X40 (0.88M dofs), but when I use 60X60X60 mesh, the program crashes and gives out some errors, which looks like a segmentation fault. The "strange" thing is that it runs well with 1CPU, 2CPUs, but fails on 4 or 8 CPUs. The log files are also attached. It seems like the global matrix and vector are assembled well, and errors come out before calling the KSPSolve().
> >
> > btw, I use the recent PETSc 3.7 dbg version. for libMesh I use both dbg and opt version, but none of those can give useful information. Has anyone met such situations before? Many thinks.
> > <ex01_validation_test.o1386940><ex01_validation_test.o1387007>
> 
>