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Georg Hager's Blog: Intel vs. GCC for the OpenMP vector triad: Barrier shootout!

Georg Hager's Blog posted an illustrative article on icc versus g++ performance w.r.t. OpenMP. Dr. Georg Hager is one of the authors of Introduction to High Performance Computing for Scientists and Engineers.

Measurement of

double precision, dimension(N) :: a,b,c,d
! initialization etc. omitted
s = walltime()
!$omp parallel private(R,i)
do R=1,NITER
!$omp do
  do i=1,N
    a(i) = b(i) + c(i) * d(i)
  enddo
!$omp end do
enddo
!$omp end parallel
e=walltime()
MFlops = R*N/(e-s)/1.e6

gives

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