On Fri, 3 Jun 2011, Barry Smith wrote: > > 2, I was using the '--with-debugging=0' to configure the PETSc. However, I > > tested the computational rate by executing the ex29.c. The non-debugging > > version does not improve the speed much; in the contrary, it slow down the > > speed a little bit. The comparison is attached here. Any idea on this. > > It depends on the compiler and particular code you are running. We > recommend using the option -log_summary to see how much time is spent in each > part of the computation and how much it gets better with optimization. >
Not sure about slowdown - but if you have prebuilt mpi with mpicc automatically using -O2 internally - you might not see a difference between --with-debugging=0 or 1 Satish
