[Omp] Help on the Barrier case

[eduncan]

Actually your program is non-compliant. If you look at the OpenMP V2.5 
specification, section 2.9 Nesting of Regions:

This section describes a set of restrictions on the nesting of regions. 
The restrictions on
nesting are as follows:
...
• A barrier region may not be closely nested inside a work-sharing, 
critical,
ordered, or master region.


That doesn't answer your question, but I thought I would point it out.

Shengyan Hong wrote:

>Every member,
>       In the ft benchmark, I add a barrier in the ft.f . The code is as 
>follows.
>"
>       !$omp parallel do default(shared) private(i,j,k)
>       do k = 1, d3
>          do j = 1, d2
>             do i = 1, d1
>                u1(i,j,k) = u0(i,j,k)*ex(t*indexmap(i,j,k))
>             end do
>          end do
>        TID = OMP_GET_THREAD_NUM()
>        PRINT *, 'thread = ', TID
>        print *, "March 6 night"
>        print *, "Before barrier"
>        CALL MAGIC_BRK_SIM_START()
>        !$OMP BARRIER
>        print *, "After barrier"
>        CALL MAGIC_BRK_SIM_START()
>        end do
>
>       return
>       end
>"
>       I run it on simics by using 8 processors with 8 threads. Now 8 
>threads enter the barrier and leave the barrier.
>       Now I have a problem. Every thread will have some time in the 
>barrier. The minimum idle time of the 8 threads is 6.493*10^3 cycles. I 
>think that there should at least one thread that has no idle 
>time in the barrier. So I am wondering whether my experiment is correct or 
>not.
>       Thank you.
>                                  Shengyan Hong
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