mirror of https://gitlab.freedesktop.org/mesa/mesa
74 lines
2.5 KiB
ReStructuredText
74 lines
2.5 KiB
ReStructuredText
u_trace GPU Performance Tracing
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===============================
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Mesa has its own GPU performance tracing framework which drivers may
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choose to implement. ``gpu.renderstages.*`` producer for
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:doc:`Perfetto Tracing <perfetto>` is based on u_trace.
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It doesn't require external dependencies and much simpler to use. Though
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it provides information only about GPU timings and is harder to analyze
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for complex rendering.
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u_trace is useful when one needs to quickly identify performance bottleneck,
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or to build a tool to analyze the raw performance data.
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Drivers which support u_trace:
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- Intel drivers: ANV, Iris
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- Adreno drivers: Freedreno, Turnip
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Usage
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-----
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u_trace is controlled by environment variables:
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.. envvar:: MESA_GPU_TRACES
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controls whether u_trace is enabled and trace output
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``print``
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prints in a human readable text format. It should be noted that this
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is mutually exclusive with ``print_json`` and both cannot be enabled
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at the same time.
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``print_json``
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prints in JSON format, suitable for parsing. Application should
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appropriately finish its rendering in order for trace's json to be
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valid. For the Vulkan API, it is expected to destroy the device,
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for GL it's expected to destroy the context.
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``perfetto``
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enables Perfetto instrumentation prior to connecting, Perfetto
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traces can be collected without setting this but it may miss some
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events prior to the tracing session being started.
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``markers``
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enables marker instrumentation, will print utrace markers into
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the CS which can then be viewed by dumping the CS from the driver.
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- For Turnip, ``cffdump`` can be used to view the markers in
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the trace.
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.. envvar:: MESA_GPU_TRACEFILE
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specifies a file where to write the output instead of ``stdout``
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.. envvar:: *_GPU_TRACEPOINT
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tracepoints can be enabled or disabled using driver specific environment
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variable. Most tracepoints are enabled by default. For instance
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``TU_GPU_TRACEPOINT=-blit,+render_pass`` will disable the
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``blit`` tracepoints and enable the ``render_pass`` tracepoints.
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.. list-table::
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:header-rows: 1
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* - Driver
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- Environment Variable
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- Tracepoint Definitions
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* - Freedreno
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- .. envvar:: FD_GPU_TRACEPOINT
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- ``src/gallium/drivers/freedreno/freedreno_tracepoints.py``
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* - Turnip
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- .. envvar:: TU_GPU_TRACEPOINT
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- ``src/freedreno/vulkan/tu_tracepoints.py``
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* - Anv
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- .. envvar:: INTEL_GPU_TRACEPOINT
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- ``src/intel/vulkan/intel_tracepoints.py``
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