[petsc-users] ISDestroy performance

[Bhalla, Amneet Pal S]

Hi Folks,

In our MG algorithm for Stokes like system we are using PETSc solvers at each level for smoothers. In particular, we are using PCASM and PCFIELDSPLIT as smoothers (with 1/2 iterations of Chebyshev or Richardson solvers).
We are also defining our own domains (IS'es) for these two PCs. The solvers at each level are initialized at the beginning of the timestep and destroyed at the end of the
timestep (it's a dynamic problem). The HPCToolKit shows that about 74% of the time is used in doing ISDestroy, whereas we expect it to use in SNES solve. This seems very weird. I also tried Instruments (OSX) just to
be sure that it was not an anomaly with HPCToolKit reporting, but the same performance sink shows up there too. Attached is the profiling from both profilers. Can anything be done to mitigate
this time sink for ISDestroy?

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20160224/e0a10dda/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Instruments_FieldsplitRun.trace.zip
Type: application/zip
Size: 4349185 bytes
Desc: Instruments_FieldsplitRun.trace.zip
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20160224/e0a10dda/attachment-0002.zip>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20160224/e0a10dda/attachment-0002.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: hpctoolkit-Fielsplit-database.zip
Type: application/zip
Size: 1674847 bytes
Desc: hpctoolkit-Fielsplit-database.zip
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20160224/e0a10dda/attachment-0003.zip>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20160224/e0a10dda/attachment-0003.htm>