docs/ci: show how to run traces locally

Newcomers may want to test traces locally and understand how the replay
works.

Acked-by: Guilherme Gallo <guilherme.gallo@collabora.com>
Signed-off-by: David Heidelberg <david.heidelberg@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17347>

docs/ci/index.rst

@@ -87,6 +87,11 @@ So the jobs are created in personal repositories, the name of the user's account
 to be added to the rules attribute of the Gitlab CI job that accesses the restricted
 accounts.
 
+.. toctree::
+   :maxdepth: 1
+
+   local-traces
+
 Intel CI
 --------
 

docs/ci/local-traces.rst

@@ -0,0 +1,45 @@
+Running traces on a local machine
+=================================
+
+Prerequisites
+-------------
+- Install `Apitrace <https://apitrace.github.io/>`_
+- Install `Renderdoc <https://renderdoc.org/>`_ (only needed for some traces)
+- Download and compile `Piglit <https://gitlab.freedesktop.org/mesa/piglit>`_ and install his `dependencies <https://gitlab.freedesktop.org/mesa/piglit#2-setup>`_
+- Download traces you want to replay from `traces-db <https://gitlab.freedesktop.org/gfx-ci/tracie/traces-db/>`_
+
+Running single trace
+--------------------
+A simple run to see the output of the trace can be done with
+
+.. code-block:: console
+
+    apitrace replay -w name_of_trace.trace
+
+For more information, look into the `Apitrace documentation <https://github.com/apitrace/apitrace/blob/master/docs/USAGE.markdown>`_.
+
+For comparing checksums use:
+
+.. code-block:: console
+
+    cd piglit/replayer
+    export PIGLIT_SOURCE_DIR="../"
+    ./replayer.py compare trace -d test path/name_of_trace.trace 0 # replace with expected checksum
+
+
+Simulating CI trace job
+-----------------------
+
+Sometimes it's useful to be able to test traces on your local machine instead of the Mesa CI runner. To simulate the CI environment as closely as possible.
+
+Download the yml file from your driver's `ci/` directory and then change the path in the yml file from local proxy or MinIO to the local directory (url-like format ``file://``)
+
+.. code-block:: console
+
+    # The PIGLIT_REPLAY_DEVICE_NAME has to match name in the yml file.
+    export PIGLIT_REPLAY_DEVICE_NAME='your_device_name'
+    export PIGLIT_REPLAY_DESCRIPTION_FILE='path_to_mesa_traces_file.yml'
+    ./piglit run -l verbose --timeout 300 -j10 replay ~/results/
+
+
+Note: For replaying traces, you may need to allow higher GL and GLSL versions. You can achieve that by setting  ``MESA_GLSL_VERSION_OVERRIDE`` and ``MESA_GL_VERSION_OVERRIDE``.