OTF2 OPEN ISSUES
                            ================
                                                           Effective: Dec 2023

This file lists known limitations and unimplemented features of
the OTF2 component.

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* Platform support

  - OTF2 has been tested on the following platforms:

    + Cray XC (see 'Shared libraries on Cray systems' below)
    + various Linux (Intel, AMD, IBM, ARM) clusters with GNU,
      Intel, NVIDIA, and IBM compilers. Note that some compilers
      are based on Clang.
    + macOS
    + MinGW (but SIONlib is known to not work on this platform)

    The provided configure options (see INSTALL) may provide a good
    basis for building and testing the toolset on other systems.

  - The following platforms have not been tested recently:

    + IBM Blue Gene/Q
    + IBM Blue Gene/P
    + Cray XT, XE, XK
    + Sun Solaris/SPARC-based clusters
    + IBM SP & BladeCenter clusters, only static libraries supported
    + SGI Altix/ICE

    However the supplied buildsystem might still work on these
    systems.

  - The following platforms have not been tested:

    + NEC SX-9
    + IBM Blue Gene/L
    + SiCortex systems
    + other NEC SX systems

  - Shared libraries on Cray systems: it is possible to build shared
    libraries on Cray systems just by using the '--enable-shared'
    configure option. Note that in order to link to these libraries,
    you need to pass the '-dynamic' flag to the compiler wrapper;
    static is the default linking mode on Cray systems.

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* Python bindings

  - Python bindings are only fully supported on AMD64.
    On other architectures, functions taking AttributeValue arguments by value
    may crash due to an issue in ctypes / libffi.

    See also:
    + https://bugs.python.org/issue26628
    + https://github.com/atgreen/libffi/issues/33

  - Definitions containing Groups of both Metrics *and* other definitions
    written by the high level otf2 module may be written in non-monotonic order
    in the trace.

  - Parallel trace processing with collective callbacks etc. is not supported
    in the high level interface

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* OTF2 misc.

  - ZLIB compression of trace files is disabled.

  - The MODIFY mode of OTF2, which can be used to rewrite time stamps
    in trace files, is untested.

  - OTF2 currently assumes "homogeneous" systems, meaning that the
    clocks of all nodes/cores run at the same clock frequency.

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Please report bugs, wishes, and suggestions to <support@score-p.org>.