| 1 | |
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| 2 | ---------------------------------------------------------------------- |
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| 3 | KNOWN ISSUES |
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| 4 | ---------------------------------------------------------------------- |
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| 5 | |
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| 6 | ### Lacking channel-specific features |
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| 7 | |
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| 8 | * ch3 does not presently support communication across heterogeneous |
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| 9 | platforms (e.g., a big-endian machine communicating with a |
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| 10 | little-endian machine). |
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| 11 | |
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| 12 | * ch3:ssm and ch3:shm do not support thread safety. |
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| 13 | |
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| 14 | * ch3:shm does not support dynamic processes (e.g., MPI_Comm_spawn). |
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| 15 | |
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| 16 | * Support for "external32" data representation is incomplete. This |
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| 17 | affects the MPI_Pack_external and MPI_Unpack_external routines, as |
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| 18 | well the external data representation capabilities of ROMIO. |
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| 19 | |
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| 20 | * ch3:dllchan is rated "experimental". There are known problems when |
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| 21 | configured with --enable-g and --enable-g=log. |
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| 22 | |
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| 23 | |
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| 24 | ### Build Platforms |
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| 25 | |
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| 26 | * ch3:nemesis does not work on Solaris. You can use ch3:sock on this |
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| 27 | platform. |
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| 28 | |
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| 29 | * ch3:ssm uses special interprocess locks (often assembly) that many |
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| 30 | not work with some compilers or machine architectures. It is known |
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| 31 | to work on Linux with GNU, Intel and Pathscale compilers and on |
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| 32 | Windows with the Visual Studio compilers, on Intel and AMD |
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| 33 | architectures. |
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| 34 | |
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| 35 | * The sctp channel is fully supported for FreeBSD and Mac OS X. As of |
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| 36 | the time of this release, bugs in the stack currently existed in |
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| 37 | the Linux kernel, and will hopefully soon be resolved. It is known |
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| 38 | to not work under Solaris and Windows. For Solaris, the SCTP API |
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| 39 | available in the kernel of standard Solaris 10 is a subset of the |
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| 40 | standard API used by the sctp channel. Cooperation with the Sun |
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| 41 | SCTP developers to support ch3:sctp under Solaris for future |
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| 42 | releases is currently ongoing. For Windows, no known kernel-based |
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| 43 | SCTP stack for Windows currently exists. |
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| 44 | |
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| 45 | |
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| 46 | ### Other configure options |
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| 47 | |
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| 48 | * --enable-sharedlibs=gcc does not work on Solaris because of |
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| 49 | difference between the GNU ld program and the Solaris ld program. |
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| 50 | |
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| 51 | |
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| 52 | ### Process Managers |
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| 53 | |
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| 54 | * The MPD process manager can only handle relatively small amounts of |
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| 55 | data on stdin and may also have problems if there is data on stdin |
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| 56 | that is not consumed by the program. |
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| 57 | |
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| 58 | * The Hydra process manager does not support dynamic processes at |
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| 59 | this time. |
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| 60 | |
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| 61 | * The SMPD process manager does not work reliably with threaded MPI |
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| 62 | processes. MPI_Comm_spawn() does not currently work for >= 256 |
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| 63 | arguments with smpd. |
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| 64 | |
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| 65 | |
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| 66 | ### Performance issues |
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| 67 | |
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| 68 | * SMP-aware collectives do not perform as well, in select cases, as |
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| 69 | non-SMP-aware collectives, e.g. MPI_Reduce with message sizes |
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| 70 | larger than 64KiB. These can be disabled by the configure option |
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| 71 | "--disable-smpcoll". |
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| 72 | |
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| 73 | * MPI_Irecv operations that are not explicitly completed before |
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| 74 | MPI_Finalize is called may fail to complete before MPI_Finalize |
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| 75 | returns, and thus never complete. Furthermore, any matching send |
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| 76 | operations may erroneously fail. By explicitly completed, we mean |
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| 77 | that the request associated with the operation is completed by one |
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| 78 | of the MPI_Test or MPI_Wait routines. |
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| 79 | |
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| 80 | * For passive target RMA, there is no asynchronous agent at the |
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| 81 | target that will cause progress to occur. Progress occurs only when |
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| 82 | the user calls an MPI function at the target (which could well be |
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| 83 | MPI_Win_free). |
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| 84 | |
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| 85 | |
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| 86 | ### C++ Binding: |
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| 87 | |
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| 88 | * The MPI datatypes corresponding to Fortran datatypes are not |
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| 89 | available (e.g., no MPI::DOUBLE_PRECISION). |
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| 90 | |
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| 91 | * The C++ binding does not implement a separate profiling interface, |
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| 92 | as allowed by the MPI-2 Standard (Section 10.1.10 Profiling). |
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| 93 | |
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| 94 | * MPI::ERRORS_RETURN may still throw exceptions in the event of an |
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| 95 | error rather than silently returning. |
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