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Subject: Re: [OMPI devel] [OMPI svn-full] svn:open-mpi r25445
From: George Bosilca (bosilca_at_[hidden])
Date: 2011-11-07 17:18:42

A little bit of history:

1. r25305: added 2 atomic operations to OPAL. However, they only exists on amd64 and are only used in the vader BTL, which I assume only supports amd64.

2. r25334: The seg_key union got a new member ptr. This member is solely used in the vader BTL, as all other BTL use a compiler trick to convert a pointer to a 64 bits.

3. r25445: All members of the seg_key union got friends, because Cray dare to set their keys at 128 bits long. However a quick
  find . -name "*.[ch]" -exec grep -Hn seg_key {} \; | grep "\[1\]"
indicates that no BTL is using 128 bits keys. Code has been added to all PMLs, but I guess they just copy empty data.

What I see is a pattern of commits that can have been dealt with differently. None had an RFC, and most of them are not even used.


On Nov 7, 2011, at 10:37 , Jeff Squyres wrote:

> On Nov 7, 2011, at 10:16 AM, Nathan T. Hjelm wrote:
>> Yes, and I completely agree. I was simply trying to keep it consistent in
>> case there is something I don't know about the heterogeneous case.
>> I increased the size of the 64 bit member because there is no uint128 type.
> Ah, I see.
> I would put the other sizes back, at a minimum. There should be no need to increase those.
> George -- comments? Should this be a new key fields (128, with 2 uint64_t's)? If this is only for large messages, is the extra 8 bytes a concern?
> --
> Jeff Squyres
> jsquyres_at_[hidden]
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