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Subject: Re: [OMPI devel] FlowChecker: Detecting Bugs in MPI Libraries via Message Flow Checking
From: Sébastien Boisvert (Sebastien.Boisvert.3_at_[hidden])
Date: 2010-11-20 12:08:14


Sounds interesting !

Regarding my bug report, I don't think it is very important.

Here's why:

According to the standard MPI 2.2, Open-MPI is correct when blocking on
any MPI_Send. So, even if Open-MPI __should__ (according to its
documentation) send messages of 4096 bytes or less eagerly (with shared
memory), the opposite is compliant too.

What I have learn is that my program should be designed and implemented
according to MPI 2.2, not Open-MPI 1.4.3 or another implementation.

On Sat, 2010-11-20 at 11:14 -0500, Christopher Samuel wrote:
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> Hi folks,
>
> At SC10 this year there was an interesting tool presented
> as a student paper called "FlowChecker: Detecting Bugs in
> MPI Libraries via Message Flow Checking".
>
> http://sc10.supercomputing.org/schedule/event_detail.php?evid=pap352
>
> Basically they instrument a program and derive "intentions"
> from your MPI calls and the MPI standard and also trace the
> data flow (including things like memcpy) and messages.Then
> offline you run a correlator which compares what was meant
> to happen and what did and tries to root cause the fault.
>
> They claim to have taken 5 random closed bugs from 3 different
> MPI implementations (including 3 from Open-MPI) and been able
> to detect all 5 and root-cause 4 of them (the one they missed
> was a data type issue).
>
> The PDF of their paper is here:
>
> http://www.cse.ohio-state.edu/~chenzhe/sc10-flowchecker.pdf
>
> I've emailed them to see if the code is going to be available
> as it could be quite a handy tool to have when trying to track
> down issues like the one Sébastien posted about.
>
> cheers,
> Chris
> - --
> Christopher Samuel - Senior Systems Administrator
> VLSCI - Victorian Life Sciences Computational Initiative
> Email: samuel_at_[hidden] Phone: +61 (0)3 903 55545
> http://www.vlsci.unimelb.edu.au/
>
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