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Whenever a single file mesa-db cache hits max size limit, a half of cache is evicted and the cache file is defragmented. The downside of this eviction strategy is that it causes high disk IO usage during eviction if mesa-db cache file size is large. In order to mitigate this downside, we will split mesa-db into multiple part such that only one part will be evicted at a time. Each part will be an individual single file mesa-db cache, like a DB shard. The new multipart mesa-db cache will merge the parts into a single virtual cache. This patch introduces two new environment variables: 1. MESA_DISK_CACHE_DATABASE_NUM_PARTS: Controls number of mesa-db cache file parts. By default 50 parts will be created. The old pre-multipart mesa-db cache files will be auto-removed if they exist, i.e. Mesa will switch to the new DB version automatically. 2. MESA_DISK_CACHE_DATABASE_EVICTION_SCORE_2X_PERIOD: Controls the eviction score doubling time period. The evicted DB part selection is based on cache entries size weighted by 'last_access_time' of the entries. By default the cache eviction score is doubled for each month of cache entry age, i.e. for two equally sized entries where one entry is older by one month than the other, the older entry will have x2 eviction score than the other entry. Database part with a highest total eviction score is selected for eviction. This patch brings x40 performance improvement of cache eviction time using multipart cache vs a single file cache due to a smaller eviction portions and more optimized eviction algorithm. Acked-by: Timothy Arceri <tarceri@itsqueeze.com> Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20256>
`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 `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://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.