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Subject: Re: [OMPI devel] [EXTERNAL] Re: r26255 has made openib unusable on Solaris platforms
From: Barrett, Brian W (bwbarre_at_[hidden])
Date: 2012-04-13 12:06:57


r2655 is awful as a patch. It doesn't work on any non-Linux platform,
which is unpleasant. But worse, what does it possibly accomplish? In
codes other than benchmarks, there's no advantage to aligning the pointer
to 32 or 64 byte boundaries, as the malloced buffer very rarely is exactly
what is sent. So you've done a whole lot of work, screwed with the memory
allocator (which always bites OMPI in the butt), and accomplished nothing
useful. Mellanox should fix the hardware, not make everyone's life
miserable with crappy workarounds.

MEMORY_LINUX_PTMALLOC2 is the wrong define for what they want. They
should check for __malloc_hook and only use that code if __malloc_hook is
found.

Brian

On 4/13/12 9:32 AM, "TERRY DONTJE" <terry.dontje_at_[hidden]> wrote:

>
>
>
> I am thinking MEMORY_LINUX_PTMALLOC2 is probably the right define to
> key off of but this is really going to look gross ifdef'ing out the
> lines that are accessing the Linux memory module. One other idea I
> have is to create a dummy __malloc_hook in the Solaris memory module
> but might there be other OSes that could run into the same
> problem? Or what happens if PTMALLOC2 is not used (does that
> happen)?
>
> --td
>
> On 4/13/2012 10:45 AM, TERRY DONTJE wrote:
>
>
> r26255 is forcing the use of __malloc_hook which is implemented in
> opal/mca/memory/linux however that is not compiled in the library
> when built on Solaris thus causing a referenced symbol not found
> when libmpi tries to load the openib btl.
>
> I am looking how to fix this now but if someone has a good idea
> how to detect when __malloc_hook is used (or not) I'd be
> interested in hearing it.
>
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> --
>
>
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>
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> Terry D. Dontje | Principal
> Software Engineer
> Developer
> Tools
> Engineering | +1.781.442.2631
>
> Oracle
>
> - Performance
> Technologies
>
> 95 Network Drive, Burlington, MA 01803
> Email terry.dontje_at_[hidden]
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-- 
  Brian W. Barrett
  Dept. 1423: Scalable System Software
  Sandia National Laboratories