35 lines
2.1 KiB
Markdown
35 lines
2.1 KiB
Markdown
# Performance and realtime qualification
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`make test-performance` runs a hardware-independent 48 kHz, 128-frame stereo
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workload: 64 graph nodes, 4096 MIDI notes (32 simultaneous), 16 tracks and gain
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automation. Preparation and block timing use CLOCK_MONOTONIC outside the engine;
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callback code itself does not clock or log. The test checks finite output and
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reports mean, p99, maximum and CPU-time/audio-duration ratio. A run is a workload
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measurement, not a universal realtime threshold. Run more blocks with:
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```sh
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./build/test_performance 10000
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```
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Initial Phase 9 measurement on an AMD Ryzen Threadripper 1920X, GCC 16.2.1, -O2,
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2000 blocks: preparation 3.045 ms, mean 308.301 us, p99 422.153 us, maximum
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665.096 us, versus a 2666.667 us block deadline; CPU/audio ratio 0.1156. These are
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one host/run's observed values and depend on scheduling/load/compiler. The test
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excludes WAV disk preparation, external/native plugin complexity, GUI redraw,
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server scheduling and actual hardware latency. Native callbacks must provide
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their own bounded realtime implementation.
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Existing software JACK loopback, stereo MIDI/save/reopen, record/reopen,
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restart/close and concurrent graph handoff tests remain available. Runtime
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fault injection covers loss/rate/xrun/null-buffer and lifecycle failures without
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altering the shared server. ASan/UBSan validate memory/error paths; TSan checks
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recorder/handoff races, not timing. Sanitized runs are not latency qualification.
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Current worst-case storage includes up to 256 MiB preloaded mono WAV samples,
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paired graph buffers (128 MiB at 256 nodes/65536 frames; GUI limit 32 MiB), bounded
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MIDI/mix metadata and up to 33 metadata/graph history snapshots. Pending/retired
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plans can retain additional graph memory. Native preparation can allocate more;
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the API cannot enforce an extension's memory budget. There is no CPU overload
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scheduler, disk streaming, latency compensation or callback allocator audit of
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arbitrary third-party code. High-density interactive projects, physical devices,
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long-duration stereo/recording and live server termination remain unqualified.
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