[Mpi3-rma] RMA proposal 1 update

[Underwood, Keith D]

Interesting. We shouldn't lose sight of the fact that lockall/unlockall when you get an exclusive lock or even when you don't assert that nobody else has an exclusive lock will be... complicated.  The advantage of lockall/unlockall is that there are usage models where it is ok to not take an exclusive lock and to assert that nobody will.  

Keith

> -----Original Message-----
> From: mpi3-rma-bounces at lists.mpi-forum.org [mailto:mpi3-rma-
> bounces at lists.mpi-forum.org] On Behalf Of William Gropp
> Sent: Wednesday, May 26, 2010 7:07 AM
> To: MPI 3.0 Remote Memory Access working group
> Cc: rbbrigh at Sandia.gov; bwbarre at Sandia.gov
> Subject: Re: [Mpi3-rma] RMA proposal 1 update
> 
> I don't think we talked about it at all - the single lock restriction
> was simply the consequence of needing a way to define the scope of
> passive target operations and support non-cache-coherent systems
> (don't forget that "lock" isn't a "lock" - its a "begin access epoch").
> 
> Bill
> 
> On May 25, 2010, at 11:28 PM, Torsten Hoefler wrote:
> 
> > On Tue, May 25, 2010 at 10:04:41PM -0600, Underwood, Keith D wrote:
> >> Lockall/unlockall was definitely on the list at the last meeting.
> >> There wasn't consensus on many things, but there was on that one ;-)
> > Ok, I added it. See wiki.
> >
> > We should still discuss this further. It seems like we're adding much
> > functionality and I'm not 100% sure if this is all compatible with
> the
> > MPI-2.0 design. Does anybody know the rationale for the one-lock
> > restriction in MPI-2?
> >
> > All the Best,
> >  Torsten
> >
> > --
> > bash$ :(){ :|:&};: --------------------- http://www.unixer.de/ -----
> > Torsten Hoefler         | Research Associate
> > Blue Waters Directorate | University of Illinois
> > 1205 W Clark Street     | Urbana, IL, 61801
> > NCSA Building           | +01 (217) 244-7736
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> 
> William Gropp
> Deputy Director for Research
> Institute for Advanced Computing Applications and Technologies
> Paul and Cynthia Saylor Professor of Computer Science
> University of Illinois Urbana-Champaign
> 
> 
> 
> 
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