[mpi3-coll] Nonblocking collectives standard draft

Christian Siebert siebert at it.neclab.eu
Tue Nov 25 11:43:34 CST 2008

Hi Torsten,

Torsten Hoefler wrote:
> Hi Christian,
>> I did a second reading and found several but only minor issues with the 
>> text. If you send me the TeX sources, I can send you my proposed 
>> corrections/improvements directly as a patch file (diff).
> I will send it via mail.
thanks - I got it. Attached is the patch file with my proposed changes.

>> - p. 49 l. 41: MPI has the concept of error handlers. I don't see a 
>> reason why we should forbid ("return an error code") its usage. My 
>> suggestion is to simply delete the two sentences (from "If the call ..." 
>> to "... cases.").
> This is actually consistent with MPI-2.1 p 48:17. I would agree to omit
> the "return an error code", but since it's already written in this style
> for point-to-point, we should keep it consistent.
Maybe - however, p 264 l 23 states "The above text takes precedence over 
any text on error handling within this document.". So the better 
alternative might be to remove these two sentences also from the p2p 
chapter instead of wrongly including it into the new nbc chapter.

>> - p. 61 l 33-38: Should we really keep this Advice for implementors 
>> (same result for MPI_IREDUCE when called with same arguments)? For the 
>> blocking variant, there stands this argument of reproducibility vs. 
>> performance. However, the non-blocking variant could be optimized much 
>> better (e.g., might handle bad process skew) and we should consider to 
>> weaken this semantic restriction to allow this better performance.
> Yes, this is a bigger issue than we assume. Reproducability is very
> important for real applications.
ok, good point.

Until tomorrow!


Christian Siebert, Dipl.-Inf.               Research Associate

            NEC Laboratories Europe, NEC Europe Ltd.
        Rathausallee 10, D-53757 Sankt Augustin, Germany

Phone: +49 (0) 2241 - 92 52 44    Fax: +49 (0) 2241 - 92 52 99

  (Registered Office: 1 Victoria Road, London W3 6BL, 2832014)
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