[mpich-discuss] Clarification needed on running processes onMPICH2

[Rajeev Thakur]

What kind of environment are you running on (how many machines, how many
cores each)? 
 
Rajeev


  _____  

From: mpich-discuss-bounces at mcs.anl.gov
[mailto:mpich-discuss-bounces at mcs.anl.gov] On Behalf Of Waruna Ranasinghe
Sent: Wednesday, November 26, 2008 2:15 AM
To: mpich-discuss at mcs.anl.gov
Subject: Re: [mpich-discuss] Clarification needed on running processes
onMPICH2


Hi Anthony,
I'm sorry, in this case I have to disagree with you.
Because it is not max(t1,t2) but t1+t2 (this is the real result I got)
I use fflush(stdout) also

What I think is that, Cluster runs two programmes alternatively.
i.e. Process A runs for a while (say t3 seconds) then process B for sometime
and so on.
Therefore, ultimately both the processes will run for t1+t2

Cluster: MPICH2
Fedora 8


2008/11/26 Anthony Chan <chan at mcs.anl.gov>



If process A and B are launched by mpiexec, the time taken
by mpiexec should be max(t1,t2) not t1 + t2. As Rajeev said,
calling fflush(stdout) after each printf() is the fastest way
to get each process's stdout printed to your console.

A.Chan

----- "Waruna Ranasinghe" <warunapww at gmail.com> wrote:

> Hi Rajeev,
> Actually this is not what I'm talking about.
> Say there are processes A and B
> Process A utilize 100% of the cpu while it runs. The answer will
> appear in
> t1 seconds
> Process B also utilize 100% of the cpu while it runs. The answer will
> appear
> in t2 seconds
>
> When I run both the process A and B at the same time, The both answers
> will
> appear in t1 + t2 seconds. where as I want to get the Process A's
> answer
> first. (Here Process A is submitted before Process B)
>
> Is there anything that I can do to make this happen.
>
> Thank You,
> Waruna
>
> 2008/11/26 Rajeev Thakur <thakur at mcs.anl.gov>
>
> >  If you are refering to the output of "printf", you can try adding
> an
> > fflush(stdout) after the printf. You don't have much control over
> the order
> > in which it is printed from different processes.
> >
> > Rajeev
> >
> >  ------------------------------
> > *From:* mpich-discuss-bounces at mcs.anl.gov [mailto:
> > mpich-discuss-bounces at mcs.anl.gov] *On Behalf Of *Waruna Ranasinghe
> > *Sent:* Tuesday, November 25, 2008 1:35 AM
> > *To:* mpich-discuss at mcs.anl.gov
> > *Subject:* [mpich-discuss] Clarification needed on running processes
> on
> > MPICH2
> >
> > Hi all,
> > I submitted 3 processes at the same time using mpiexec. the results
> of each
> > process appears only after all the processes have finished. (I guess
> that
> > the way mpich schedule it).
> > What if I want to get the result of the process, which was submitted
> first,
> > first. (like first in first out).
> >
> > I use MPICH2 cluster in Fedora 8 (with mpd)
> >
> > Thank you.
> > Waruna Ranasinghe
> >
> >



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