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Subject: Re: [OMPI users] Regarding the execution time calculation
From: Jingcha Joba (pukkimonkey_at_[hidden])
Date: 2012-05-04 18:08:06


Lets say I have a code like this

start = MPI_Wtime()
<Run the solver>
stop = MPI_Wtime();

What happens when right after start=MPI_Wtime(), the timeslice of the
process ( from the operating system's perspective not the MPI process) is
over, and the operating system schedules a next process, after saving the
context switch, and eventually this application would resume, once its
process is scheduled back by the os.

Does MPI_Wtime() takes care of storing/updating the time when this happens?

Of course, part of the answer lies in the implementation of Wtime.

On Fri, May 4, 2012 at 3:53 AM, Jeff Squyres <jsquyres_at_[hidden]> wrote:

> On May 3, 2012, at 2:02 PM, Jingcha Joba wrote:
>
> > Not related to this question , but just curious, is Wtime context switch
> safe ?
>
> Not sure exactly what you're asking here...?
>
> --
> Jeff Squyres
> jsquyres_at_[hidden]
> For corporate legal information go to:
> http://www.cisco.com/web/about/doing_business/legal/cri/
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>
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