44 lines
1.4 KiB
ReStructuredText
44 lines
1.4 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:`GPU_TRACE`
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if set to ``1`` enables tracing and outputs the data into ``stdout``
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:envvar:`GPU_TRACEFILE`
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specifies a file where to write the output instead of ``stdout``
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:envvar:`GPU_TRACE_FORMAT`
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controls a format of the output
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``txt``
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human readable text format
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``json``
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json format, suitable for parsing. Application should appropriately
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finish its rendering in order for trace's json to be valid.
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For Vulkan api it is expected to destroy the device, for GL it is
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expected to destroy the context.
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:envvar:`GPU_TRACE_INSTRUMENT`
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Meaningful only for Perfetto tracing. If set to ``1`` enables
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instrumentation of GPU commands before the tracing is enabled.
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