[MPICH2-dev] RE: alignment hints for calculating the file domain.

[Robert Latham]

On Tue, Jul 10, 2007 at 08:55:18AM -0400, Yu, Weikuan wrote:
> Wangdi has observed a lot of lock contentions when the file domain
> partitions in collective IO are not aligned on Lustre stripe boundary
> (say 1MB). As a remedy of that, we are proposing a minor change on the
> implementation of ADIOI_GEN_Calc_file_domains() for it to respect an
> advisory alignment. The attached patch illustrates what we are
> proposing. 

Ok, so you turn fd_size from an output parameter to an in/out
parameter.  I don't think that's introducing noticeably more
complexity to the interface.  

Before you call calc_file_domains, how will you set fd_size?  Through
a hint the user can override? 

> P.S.: We will use mpich-discuss at mcs.anl.gov for further discussions if
> mpich2-dev is not for this purpose.

I think this list will be fine.

==rob

-- 
Rob Latham
Mathematics and Computer Science Division    A215 0178 EA2D B059 8CDF
Argonne National Lab, IL USA                 B29D F333 664A 4280 315B