[petsc-users] CPU time of PETSc

[Qin Lu]

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.
2. The same program gets consistent cpu time and elapse time in Linux. Do you have any idea why?
 
Thanks for any suggestions.
Qin
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