Tim Van Patten c585341552 intel/ds: Skip expensive timestamp query until necessary
The Xe ioctl DRM_XE_DEVICE_QUERY_ENGINE_CYCLES provides accurate
timestamps correlated between the CPU and GPU. However, it is slow and
impacts performance while collecting Perfetto traces.

Instead, use Perfetto's GetBootTimeNs() to track when to emit the
BUILTIN_CLOCK_BOOTTIME clock sync event so it only occurs every 1
second. This reduces the impact of recording gpu.renderstages from
-8% to -4%.

More concretely, FPS measurements when tracing Unity BoatAttack demo on
an Intel ADL device:

* gpu.renderstages disabled:            48.044293667
* gpu.renderstages enabled:             38.119778333 (-20.66%)
* gpu.renderstages enabeled + this fix: 42.641818333 (-11.24%)

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/37095>
2025-08-29 21:34:43 +00:00
2025-02-23 00:31:59 +01:00
2025-08-27 21:12:41 -04:00
2025-01-08 20:37:51 +00:00
2025-02-09 08:13:27 +00:00
2023-11-02 11:37:46 +00:00
2025-07-24 16:12:10 +00:00
2025-07-26 00:33:59 +00:00
2024-11-18 22:29:14 +00:00
2025-07-16 13:50:24 +00:00

`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.
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