> On Jul 20, 2019, at 9:58 PM, Mohammed Mostafa <mo7ammedmost...@gmail.com> > wrote: > > Hello Barry, > > > In runs did you zero the matrix before call the MatSetValues() initially? > > > I only zero the matrix when using add_values insert mode but otherwise I > don’t
Is there any reason to use ADD_VALUES? Since you need to insert each value for an individual column/row exactly once? In the timings you sent did you zero the matrix before? Does it make a difference in the timing for setting values into there matrix? Barry > > > > What kind of a processor is this? > This is an i7-Processor 6 core 3.9Ghz if I can remember correctly > I tried it on another intel Xeon processor 14 core but using only 6 processor > and I got a similar trend with increasing nrow buffer > > > Would you be able to run the code under gprof, vtune, instruments or > > something profiling package that gives line by line information about time > > being spent. In particular I'd like to see the results for MatSetValues(), > > MatSetValues2() with 1 row, with 2, rows and with 4 rows. > > > I will try to do that but I am currently traveling to attend a conference so > I can not get back to you on that until Thursday > > > Regards, > Kamra > > > > On Jul 20, 2019, at 8:59 AM, Smith, Barry F. <bsm...@mcs.anl.gov> wrote: > > > > In runs did you zero the matrix before call the MatSetValues() initially? > > > > > >> MatSetValues() > >> FillPetscMat 3.6594e+00 > >> MatSetValues2_MPIAIJ() with an nrow_buffer = 1 > >> FillPetscMat 13.3920e+00 > >> nrow_buffer = 2 > >> FillPetscMat_with_MatSetValues2 3.3321e+00 > >> nrow_buffer = 5 > >> FillPetscMat_with_MatSetValues2 2.8842e+00 > >> nrow_buffer = 10 > >> FillPetscMat_with_MatSetValues2 2.7669e+00 > >> nrow_buffer = 20 > >> FillPetscMat_with_MatSetValues2 2.6834e+00 > >> nrow_buffer = 50 > >> FillPetscMat_with_MatSetValues2 2.6862e+00 > >> nrow_buffer = 100 > >> FillPetscMat_with_MatSetValues2 2.6170e+00 > >> > > > > The call to MatSetValues() has a little bit of checking and then another > > call to MatSetValues_MPIAIJ() so it is not surprising that going directly > > to MatSetValues_MPIAIJ2() saves you a bit but it is a large savings than I > > would expect. > > > > I am greatly puzzled by the dramatic savings you get as you pass more rows > > to MatSetValues2. As far as I can see all you are saving is a function > > call, not much of anything else and that would NOT explain the huge time > > savings (functions calls are extremely cheap compared to .5 seconds. The > > multi row MatSetValues2() still has to do the same processing as with one > > call per row so why so much faster? > > > > What kind of a processor is this? > > > > Would you be able to run the code under gprof, vtune, instruments or > > something profiling package that gives line by line information about time > > being spent. In particular I'd like to see the results for MatSetValues(), > > MatSetValues2() with 1 row, with 2, rows and with 4 rows. > > > > > > > > Thanks > > > > Barry
