manual:known_issues
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| — | manual:known_issues [2016/09/01 07:13] (current) – created zenke | ||
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| + | ====== Known Issues ====== | ||
| + | |||
| + | * Spike-loss and random crashes experienced with with process numbers that were not a power of two. (OpenMPI 1.4.3) | ||
| + | * Random communication freezes for large messages (i.e. caused by synchronization in the network -> many spikes in short time intervals). | ||
| + | * Still getting random freezes when running v0.8.0-beta on Ubuntu 14.04 LTS with the stock openmpi (Open MPI 1.6.5) | ||
| + | |||
| + | I traced the freezes to SyncBuffer at high firing rates or high synchrony. In most cases it seems as if some processes do not recover from MPI_Allgather when resending the buffer after an overflow. To reproduce run | ||
| + | |||
| + | < | ||
| + | mpirun -n 4 ./ | ||
| + | </ | ||
| + | |||
| + | or for instance | ||
| + | |||
| + | < | ||
| + | mpirun -n 4 ./ | ||
| + | </ | ||
| + | |||
| + | Note, that -n 2 seems to work and 3 or 5 cause other weird problems. Looks like a bug in openmpi. | ||
| + | When compiled against MPICH these problems do not occur. | ||
manual/known_issues.txt · Last modified: 2016/09/01 07:13 by zenke