[Pvfs2-developers] Unexpected file distribution with MPI-programs using the MPI hint striping_unit

[Robert Latham]

On Sun, Mar 04, 2007 at 03:23:30PM +0100, Julian Martin Kunkel wrote:
> I found some unexpected behavior in the distribution behavior if I
> set in  MPI-programs the MPI hint striping_unit to (whatever) value.

Thanks for the bug report.  This one was rather gross.  I've attached a patch
to fix it.  

Turns out when you pass a pointer-to-int instead of a pointer-to-int64
to a function that takes a void*, you get garbled data and a strp size
of 584382286904951784 bytes.  that's 0x81c2498000003e8, and 0x3e8 ==
1000 (8 bytes of real data and 8 bytes of random memory).

Sam's come up with a proposal to make this sort of bug harder to
trigger.  We can discuss that in a separate thread. 

==rob

-- 
Rob Latham
Mathematics and Computer Science Division    A215 0178 EA2D B059 8CDF
Argonne National Lab, IL USA                 B29D F333 664A 4280 315B
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PatchSet 1159 
Date: 2007/03/07 06:14:31
Author: robl
Branch: HEAD
Tag: (none) 
Log:
pass the proper type to  PVFS_sys_dist_setparam

Members: 
	adio/ad_pvfs2/ad_pvfs2_open.c:1.29->1.30 

Index: romio/adio/ad_pvfs2/ad_pvfs2_open.c
diff -u romio/adio/ad_pvfs2/ad_pvfs2_open.c:1.29 romio/adio/ad_pvfs2/ad_pvfs2_open.c:1.30
--- romio/adio/ad_pvfs2/ad_pvfs2_open.c:1.29	Wed Oct 18 08:06:50 2006
+++ romio/adio/ad_pvfs2/ad_pvfs2_open.c	Wed Mar  7 12:14:31 2007
@@ -30,7 +30,7 @@
      * handle to everyone else in the communicator
      */
 static void fake_an_open(PVFS_fs_id fs_id, char *pvfs_name, int access_mode,
-	                 int nr_datafiles, int strip_size,
+	                 int nr_datafiles, PVFS_size strip_size,
                          ADIOI_PVFS2_fs *pvfs2_fs, 
 			 open_status *o_status)
 {