AMPI_Alltoall crashes for short messages
Running the megampi test for more number of ranks(instead of 4) crashes with a memory corruption. More investigation points to MPI_Alltoall test.
#3 Updated by Karthik Senthil over 2 years ago
I think there are multiple bugs associated with this issue.
1. When I run the test as
./pgm +vp 5, the program crashes with
pgm: malloc.c:3695: _int_malloc: Assertion `(unsigned long) (size) >= (unsigned long) (nb)' failed
With GDB this points to a call within the MPI_COMM_SELF tests that are performed in megampi.
2. When I run the test as
./pgm +vp 7, a mismatch of expected value for the Alltoall test is obtained. I am tracing the current recursive doubling algorithm to fix this.
As a temporary fix we can use the medium size messages algorithm for the short messages as well. Interestingly this solves both the above bugs.