Open MPI logo

Open MPI User's Mailing List Archives

  |   Home   |   Support   |   FAQ   |  

This web mail archive is frozen.

This page is part of a frozen web archive of this mailing list.

You can still navigate around this archive, but know that no new mails have been added to it since July of 2016.

Click here to be taken to the new web archives of this list; it includes all the mails that are in this frozen archive plus all new mails that have been sent to the list since it was migrated to the new archives.

Subject: Re: [OMPI users] Regarding the execution time calculation
From: Jingcha Joba (pukkimonkey_at_[hidden])
Date: 2012-05-07 20:31:00


Jeff,
So in the above stated example, end-start will be: <whatever the solver
took> + 20ms ?

(time slice of P2 + P3 = 20ms)

On Mon, May 7, 2012 at 1:42 PM, Jeff Squyres (jsquyres)
<jsquyres_at_[hidden]>wrote:

> On May 7, 2012, at 2:39 PM, Jingcha Joba wrote:
>
> > OK.This explains that if a process gets "migrated" from one CPU to
> another, the time is not "affected". But it still doesn't explain if the
> process gets scheduled back to the same CPU.
>
> MPI_Wtime() doesn't tell you any of this stuff. It just tells you the
> time *right now*. Basically, MPI_Wtime() can be used to compute wall-clock
> timings (which are really the only relevant timings when measuring
> delivered performance, anyway).
>
> What happens before or after that is not covered in the scope of
> MPI_Wtime().
>
> --
> Jeff Squyres
> jsquyres_at_[hidden]
> For corporate legal information go to:
> http://www.cisco.com/web/about/doing_business/legal/cri/
>
>
> _______________________________________________
> users mailing list
> users_at_[hidden]
> http://www.open-mpi.org/mailman/listinfo.cgi/users
>