Lustre discuss - Jan 2010 - adio lustre patch

Hello,

I took a look at the ADIO Lustre driver last week in an attempt to make 
collective I/O work for my application. I believe that I''ve gotten the 
driver to do the right thing now. With the following patch all of the 
tests under romio/test pass in my environment. My application, which 
requires reasonably complex file views, also appears to write correct 
files now on a Lustre filesystem using collective I/O.

Problems in the noncontig and i_noncontig tests are fixed by changes to 
ad_lustre_wrstr.c. Basically, I made changes to that file so that it now 
more closely matches adio/common/ad_write_str.c. The only differences in 
these files should now be in the Lustre-specific parts. Problems in the 
large_array test are fixed in ad_lustre_aggregate.c and 
ad_lustre_wrcoll.c. The major problem was in the handling of the 
"buf_idx" arrays, which were not correctly tracking the data out of a 
process''s data buffer being sent to multiple other processes. My tests 
involved four MPI nodes, four Lustre OSTs and both four and eight MPI 
processes.

I also patched ad_lustre_aggregate in its calculation of 
"avail_cb_nodes" as previously provided by Pascal Deveze. I
don''t know
whether that has had any effect on my changes, since I did no testing 
without Pascal''s changes.

There are some other changes, such as formatting and the addition of 
some assertions. They are included in the attached patch, but I could 
take them out if desired.

The patch should apply cleanly to sources out of a fresh mpich2-1.2.1 
tarball. I''m not an old hand at MPI, so please review my patch
carefully.

-- 
Martin

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On Mon, Jan 04, 2010 at 11:09:28AM -0700, Martin Pokorny
wrote:
> Hello,
> 
> I took a look at the ADIO Lustre driver last week in an attempt to
> make collective I/O work for my application. I believe that I''ve
> gotten the driver to do the right thing now. With the following
> patch all of the tests under romio/test pass in my environment. My
> application, which requires reasonably complex file views, also
> appears to write correct files now on a Lustre filesystem using
> collective I/O.
Hi! Thanks for taking a closer look at the ad_lustre driver.  Emoly
Liu sent me an updated patch shortly before the winter break as well.
I will follow up with that message.  

I haven''t taken a close look yet at either patch but I hope it
won''t
be hard to merge the two and finally take care of all the remaining
bugs.

==rob

-- 
Rob Latham
Mathematics and Computer Science Division
Argonne National Lab, IL USA