On Fri, Dec 6, 2013 at 1:51 PM, Qin Lu <[email protected]> wrote:
> Hello, > > I am using serial PETSc linear solver in a serial Fortran program, which > uses function CPU_TIME() to count cpu time. In Windows-7, the cpu time > turns out to be 2 to 3 times as much as elapse time. My questions are: > > 1. Does PETSc internally use multi-thread even though I configured it with > --useThreads=0? I ask so since it is known that CPU_TIME() adds the cpu > time of all threads togather. > No. > 2. The same program gets consistent cpu time and elapse time in Linux. Do > you have any idea why? > I am guessing your normalization is wrong. Why not just use -log_summary? We test for these things. Matt > Thanks for any suggestions. > Qin > -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener
