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Even though the hardware does not naively support these configurations, there are many potential benefits to advertising them. These configurations can theoretically use half the memory bandwidth for loads and stores. For large matrices, that can be the limiting in performance. The current implementation, however, has a number of significant problems. The conversion from float16 to float32 is performed in the driver during conversion from NIR. As a result, many common usage patterns end up doing back-to-back conversions to and from float16 between matrix multiplications (when the result of one multiplication is used as the accumulator for the next). The float16 version of the matrix waste half the possible register space. Each float16 value sits alone in a dword. This is done so that the per-invocation slice of an 8x8 float16 result matrix and an 8x8 float32 result matrix will have the same number of elements. This makes it possible to do straightforward implementations of all the unary_op type conversions in NIR. It would be possible to perform N:M element type conversions in the backend using specialized NIR intrinsics. However, per #10961, this would be very, very painful. My hope is that, once a suitable resolution for that issue can be found, support for these configs can be restored. Reviewed-by: Caio Oliveira <caio.oliveira@intel.com> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28834>
`Mesa <https://mesa3d.org>`_ - The 3D Graphics Library ====================================================== Source ------ This repository lives at https://gitlab.freedesktop.org/mesa/mesa. Other repositories are likely forks, and code found there is not supported. Build & install --------------- You can find more information in our documentation (`docs/install.rst <https://docs.mesa3d.org/install.html>`_), but the recommended way is to use Meson (`docs/meson.rst <https://docs.mesa3d.org/meson.html>`_): .. code-block:: sh $ mkdir build $ cd build $ meson .. $ sudo ninja install Support ------- Many Mesa devs hang on IRC; if you're not sure which channel is appropriate, you should ask your question on `OFTC's #dri-devel <irc://irc.oftc.net/dri-devel>`_, someone will redirect you if necessary. Remember that not everyone is in the same timezone as you, so it might take a while before someone qualified sees your question. To figure out who you're talking to, or which nick to ping for your question, check out `Who's Who on IRC <https://dri.freedesktop.org/wiki/WhosWho/>`_. The next best option is to ask your question in an email to the mailing lists: `mesa-dev\@lists.freedesktop.org <https://lists.freedesktop.org/mailman/listinfo/mesa-dev>`_ Bug reports ----------- If you think something isn't working properly, please file a bug report (`docs/bugs.rst <https://docs.mesa3d.org/bugs.html>`_). Contributing ------------ Contributions are welcome, and step-by-step instructions can be found in our documentation (`docs/submittingpatches.rst <https://docs.mesa3d.org/submittingpatches.html>`_). Note that Mesa uses gitlab for patches submission, review and discussions.