Two short questions: do you have any open MPI mca parameters set in a
file or at runtime? And second, is there any difference if you disable
the hierarch coll module (which does communicate additionally as well?) e.g.
mpirun --mca coll ^hierarch -np 4 ./mytest
Thanks
Edgar
Thomas Ropars wrote:
Ashley Pittman wrote:
On Wed, 2009-09-09 at 17:44 +0200, Thomas Ropars wrote:
Thank you. I think you missed the top three lines of the output but
that doesn't matter.
main() at ?:?
PMPI_Comm_dup() at pcomm_dup.c:62
ompi_comm_dup() at communicator/comm.c:661
-----------------
[0,2] (2 processes)
-----------------
ompi_comm_nextcid() at communicator/comm_cid.c:264
ompi_comm_allreduce_intra() at communicator/comm_cid.c:619
ompi_coll_tuned_allreduce_intra_dec_fixed() at
coll_tuned_decision_fixed.c:61
ompi_coll_tuned_allreduce_intra_recursivedoubling() at
coll_tuned_allreduce.c:223
ompi_request_default_wait_all() at request/req_wait.c:262
opal_condition_wait() at ../opal/threads/condition.h:99
-----------------
[1,3] (2 processes)
-----------------
ompi_comm_nextcid() at communicator/comm_cid.c:245
ompi_comm_allreduce_intra() at communicator/comm_cid.c:619
ompi_coll_tuned_allreduce_intra_dec_fixed() at
coll_tuned_decision_fixed.c:61
ompi_coll_tuned_allreduce_intra_recursivedoubling() at
coll_tuned_allreduce.c:223
ompi_request_default_wait_all() at request/req_wait.c:262
opal_condition_wait() at ../opal/threads/condition.h:99
Lines 264 and 245 of comm_cid.c are both in a for loop which calls
allreduce() twice in a loop until a certain condition is met. As such
it's hard to tell from this trace if it is processes [0,2] are "ahead"
or [1,3] are "behind". Either way you look at it however the
all_reduce() should not deadlock like that so it's as likely to be a bug
in reduce as it is in ompi_comm_nextcid() from the trace.
I assume all four processes are actually in the same call to comm_dup,
re-compiling your program with -g and re-running padb would confirm this
as it would show the line numbers.
Yes they are all in the second call to comm_dup.
Thomas
Ashley,
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Edgar Gabriel
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Parallel Software Technologies Lab http://pstl.cs.uh.edu
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