Connor Abbott
50aa66a7c1
The mechanism implemented in the hardware to synchronize against Write after Read hazards with the visibility stream for concurrent binning is for BV and BR to keep track of the number of render passes they have finished and BV waits until BR_count >= BV_count - vis stream count. For example, if there are two visibility streams and the user submits three renderpasses, before starting renderpass #3 BV will wait for BR to finish renderpass #1. It's assumed that renderpass #3 and #2 use different visibility streams, so it's safe to start working on #3 once #2 is done. This mechanism is assumed to work across renderpasses and even submits, and the only way to reset the BR/BV counts is via CP_RESET_CONTEXT_STATE which is only done by the kernel when switching contexts. This vastly complicates things for Vulkan, where we have no idea what order command buffers will be submitted. This means that we have to defer emitting the actual pointers until submission time and create patchpoints instead. This gets unfortunately very complicated with SIMULTANEOUS_USE_BIT where we have to update the patchpoints on the GPU. I've taken the liberty of also deferring the allocation of the visibility stream until submit time. This will help us later move to per-queue visibility streams, which will be necessary for supporting multiple simultaneous queues. Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36590>
`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 $ meson setup build $ ninja -C build/ $ sudo ninja -C build/ 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.