This sounds reasonable.
Walt
Sam Lang wrote:
On Mar 7, 2007, at 12:32 PM, Robert Latham wrote:
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.
My proposal is to change the PVFS_dist_set_param call to take the
entire distribution param struct, instead of individual fields within
that struct. This would force callers to first get the current
parameters, so that they weren't overwriting fields that had already
been set, but it would prevent the type error that occurred above.
Also, for distributions with many parameters (instead of just one like
simple stripe), it would probably be easier to do:
struct crazy_dist_params params;
get_params(¶ms);
params.param1 = 100;
...
params.paramN = "hi";
set_params(¶ms);
Currently, we would have to call set_param for each field.
In PINT_dist_default_set_param, we get the offset into the param struct
based on the field name. Sort of a home-baked runtime reflection in
C. I think we could avoid all that by just passing in the entire param
struct.
-sam
==rob
--
Rob Latham
Mathematics and Computer Science Division A215 0178 EA2D B059 8CDF
Argonne National Lab, IL USA B29D F333 664A 4280 315B
<sys_dist_setparam.patch>
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--
Dr. Walter B. Ligon III
Associate Professor
ECE Department
Clemson University
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