63 lines
2.0 KiB
ReStructuredText
63 lines
2.0 KiB
ReStructuredText
u_trace GPU Performance Tracing
|
|
===============================
|
|
|
|
Mesa has its own GPU performance tracing framework which drivers may
|
|
choose to implement. ``gpu.renderstages.*`` producer for
|
|
:doc:`Perfetto Tracing <perfetto>` is based on u_trace.
|
|
|
|
It doesn't require external dependencies and much simpler to use. Though
|
|
it provides information only about GPU timings and is harder to analyze
|
|
for complex rendering.
|
|
|
|
u_trace is useful when one needs to quickly identify performance bottleneck,
|
|
or to build a tool to analyze the raw performance data.
|
|
|
|
Drivers which support u_trace:
|
|
- Intel drivers: Anv, Iris
|
|
- Adreno drivers: Freedreno, Turnip
|
|
|
|
Usage
|
|
-----
|
|
|
|
u_trace is controlled by environment variables:
|
|
|
|
:envvar:`GPU_TRACE`
|
|
if set to ``1`` enables tracing and outputs the data into ``stdout``
|
|
|
|
:envvar:`GPU_TRACEFILE`
|
|
specifies a file where to write the output instead of ``stdout``
|
|
|
|
:envvar:`GPU_TRACE_FORMAT`
|
|
controls a format of the output
|
|
|
|
``txt``
|
|
human readable text format
|
|
``json``
|
|
json format, suitable for parsing. Application should appropriately
|
|
finish its rendering in order for trace's json to be valid.
|
|
For Vulkan api it is expected to destroy the device, for GL it is
|
|
expected to destroy the context.
|
|
|
|
:envvar:`GPU_TRACE_INSTRUMENT`
|
|
Meaningful only for Perfetto tracing. If set to ``1`` enables
|
|
instrumentation of GPU commands before the tracing is enabled.
|
|
|
|
:envvar:`*_GPU_TRACEPOINT`
|
|
tracepoints can be enabled or disabled using driver specific environment
|
|
variable. Most tracepoints are enabled by default. For instance
|
|
``TU_GPU_TRACEPOINT=-blit,+render_pass`` will disable the
|
|
``blit`` tracepoints and enable the ``render_pass`` tracepoints.
|
|
|
|
.. list-table::
|
|
:header-rows: 1
|
|
|
|
* - Driver
|
|
- Environment Variable
|
|
- Tracepoint Definitions
|
|
* - Freedreno
|
|
- :envvar:`FD_GPU_TRACEPOINT`
|
|
- ``src/gallium/drivers/freedreno/freedreno_tracepoints.py``
|
|
* - Turnip
|
|
- :envvar:`TU_GPU_TRACEPOINT`
|
|
- ``src/freedreno/vulkan/tu_tracepoints.py``
|