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Hi Rob,<br>
<br>
I encounter the problem with version mpich2-1.2.1p. This is one of the
latest.<br>
To see the buffer corruption, just change your test at line 57:<br>
<pre wrap="">if (buffer[i] != cmp[i]) // i instead of 0 (this will help)
I confirm you that the problem still behaves like my original test.
Pascal
</pre>
<br>
<br>
<br>
Rob Latham a écrit :
<blockquote cite="mid:20100831180635.GG9244@mcs.anl.gov" type="cite">
<pre wrap="">On Mon, Aug 23, 2010 at 04:35:36PM +0200, Pascal Deveze wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Here is a little program to reproduce it: It writes 5 bytes on a
file (0,1,2,3,4) and two MPI processes try to read 10 bytes.
The read are succeeded and the 5 read bytes are correct, but:
1) The count value is set to 10 (instead of 5 because only 5 valid
bytes are read).
2) The 5 last bytes of the read buffers are overwritten (in this
case the values 99 are erased by 0)
</pre>
</blockquote>
<pre wrap=""><!---->
Hi Pascal
I don't see any buffer corruption problem with a recent MPICH2
checout, but I can confirm the get_count problem.
I do see the buffer problem with OpenMPI-1.4, but we have not synced
up ROMIO versions for about two years now. we must have fixed things
in the meantime. What MPI version are you testing?
I have made some very small modifications to your test example to make
it more like other romio tests. Can you confirm the test still
behaves like your original test?
- have only rank 0 write the file
- introduce a sync/barrier/sync to ensure MPI_File_write and
MPI_File_read_all are in separate access epochs.
- first argument (argv[1]) is the file name.
- more precisely specify where the bad elements in buffer lie.
Thanks!
==rob
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<pre wrap=""><pre wrap="">
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