Iago Toral Quiroga
bed3f31fc6
Dedicated BOs waste memory and are also a significant cause of CPU overhead when applications use hundreds of them per frame due to all the work the kernel has to do to page in all these BOs for a job. The UE4 Vehicle demo was hitting this causing it to freeze and stutter under 1fps. The hardware allows us to setup groups of 16 queries in consecutive 4-byte addresses, requiring only that each group of 16 queries is aligned to a 1024 byte boundary. With this change, we allocate all the queries in a pool in a single BO and we assign them different offsets based on the above restriction. This eliminates the freezes and stutters in the Vehicle sample. One caveat of this solution is that we can only wait or test for completion of a query by testing if the GPU is still using its BO, which basically means that we can only wait for all active queries in a pool to complete and not just the ones being requested by the API. Since the Vulkan recommendation is to use a different query pool per frame this should not be a big issue though. If this ever becomes a problem (for example if an application does't follow the recommendation and instead allocates a single pool and splits its queries between frames), we could try to group queries in a pool into a number of BOs to try and find a balance, but for now this should work fine in most cases. Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10253>
`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://mesa3d.org/install.html>`_), but the recommended way is to use Meson (`docs/meson.rst <https://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 `Freenode's #dri-devel <irc://chat.freenode.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://mesa3d.org/bugs.html>`_). Contributing ------------ Contributions are welcome, and step-by-step instructions can be found in our documentation (`docs/submittingpatches.rst <https://mesa3d.org/submittingpatches.html>`_). Note that Mesa uses gitlab for patches submission, review and discussions.