Optimize render-loop output path#2
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Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Pull request overview
This PR optimizes the Core Audio callback hot path in RenderLoopProcessor by reducing allocations and per-sample overhead during input snapshotting and output writes.
Changes:
- Pre-reserve capacities when building input/output snapshots to reduce allocations.
- Replace
map+reducewith a single-pass capacity calculation inoutputSnapshot. - Speed up output writes by caching counts, using early termination, and switching single-buffer writes to
memcpy.
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| } else if sampleIndex < mixedSampleCount { | ||
| outputSamples[sampleIndex] = mixedSamples[sampleIndex] | ||
| writtenSampleCount += 1 | ||
| } else { | ||
| break | ||
| } |
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| samples.withUnsafeBufferPointer { sourceBuffer in | ||
| memcpy( | ||
| outputSamples, | ||
| sourceBuffer.baseAddress, | ||
| writtenSampleCount * MemoryLayout<Float>.stride | ||
| ) |
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Summary
Why this change
This is a high-impact, low-effort improvement because it targets the Core Audio callback path (AudioRenderLoop) where even small per-callback savings compound quickly under sustained playback.