Juq-089-mosaic-javhd-today-1230202202-29-19 Min -

| Issue | Root Cause | Evidence | |-------|------------|----------| | FPS shortfall (‑4 %) | Lock‑contention on tile‑stitching barrier when all 8 threads converge each frame. | Thread‑dump shows 2‑3 threads waiting ~0.8 ms per frame. | | Latency +7 ms | Decoder queue depth too low for burst‑load on 4K frames, causing occasional back‑pressure. | jvisualvm shows queue size hitting max (5) 12× during test. |

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A. Log excerpts – See attached juq089_20221230_log.txt. JUQ-089-MOSAIC-JAVHD-TODAY-1230202202-29-19 Min

B. CSV Metrics – juq089_20221230_metrics.csv (timestamp, FPS, latency, CPU%, GPU%, HeapMB, GCms). | Issue | Root Cause | Evidence |

C. Thread Dump (snapshot @ 12:15 UTC) – Highlights barrier wait times. | Step | Action | Expected Result |

D. Test Script – run_juq089.sh (Bash wrapper used on the Windows subsystem).

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| Step | Action | Expected Result | |------|--------|-----------------| | 1 | Launch javhd‑stress‑v2.jar with flags ‑tiles=8 ‑‑debug | Application starts, logs initialization. | | 2 | Load the 4K test clip; begin playback. | Playback begins within 0.5 s. | | 3 | Enable MOSAIC tiling; monitor tile‑stitching latency. | Stitching latency ≤ 5 ms per tile. | | 4 | Run for 19 minutes (29 seconds of actual video playback, repeated loop). | No crashes, stable memory. | | 5 | Capture metrics every 5 seconds (fps, latency, GPU/CPU usage, GC pauses). | Data logged to report_juq089_20221230.csv. | | 6 | Graceful shutdown; export logs & heap dump. | All logs archived, heap dump < 2 GB. |

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