Published by Sean Carr
Automated 30-Minute Engine Soak Testing: Measuring Frame Latency and Memory Drift
Continuous headless playtesting on Crown and Claim (native Vulkan): sub-8ms worst-frame latency and zero private memory leaks.
At a Glance
Worst-Frame p50 Latency
7.88 ms
Median worst-case frame time held comfortably under the 8.33 ms (120 fps) budget ceiling.
Private Memory Growth
-0.08 MB / min
Private byte allocation was flat over 30 minutes, confirming zero memory leaks.
Input Delivery Ratio
0.9997
Continuous agent input delivery was maintained with zero command buffer dropped packets.
Clean Swapchain Frames
900 / 900 Frames
Full sampled presentation window presented without fallback skips or tearing.
| Telemetry Metric | Measured Value | Context & Observability |
|---|---|---|
| Worst-Frame p50 Latency | 7.88 ms | Median worst-case frame time held comfortably under the 8.33 ms (120 fps) budget ceiling. |
| Private Memory Growth | -0.08 MB / min | Private byte allocation was flat over 30 minutes, confirming zero memory leaks. |
| Input Delivery Ratio | 0.9997 | Continuous agent input delivery was maintained with zero command buffer dropped packets. |
| Clean Swapchain Frames | 900 / 900 Frames | Full sampled presentation window presented without fallback skips or tearing. |
Published by Sean Carr
View & print executive brief version →Executive Summary & Core Finding
Short 30-second rendering benchmarks often mask slow-burn memory leaks, shader cache thrashing, and asset streaming degradation. In Atlas Engine, we deployed autonomous playtest agents to execute continuous 30-minute traversals (9.5+ km across 53 streaming regions), measuring steady sub-8ms worst-frame p50 latencies and zero private byte accumulation.
Method
Automated agent playtest harness executing continuous movement and camera sweeps in Crown and Claim (Vulkan 3840x2160 native).
Continuous 1,800-second (30-minute) soak traversing 9,595 meters of terrain and streaming 53 regional asset sectors.
Hardware timestamp profiling tracking per-frame GPU execution, swapchain present times, and CPU staging latency.
Process memory monitoring tracking Working Set, Private Bytes, and VMA device heap allocations at 1-second intervals.
What We Measured
Soak test telemetry across 1,800 seconds and 9,595 meters traversal
Worst-Frame p50 Latency
7.88 ms
Median worst-case frame time held comfortably under the 8.33 ms (120 fps) budget ceiling.
Private Memory Growth
-0.08 MB / min
Private byte allocation was flat over 30 minutes, confirming zero memory leaks.
Input Delivery Ratio
0.9997
Continuous agent input delivery was maintained with zero command buffer dropped packets.
Clean Swapchain Frames
900 / 900 Frames
Full sampled presentation window presented without fallback skips or tearing.
Experimental Notes & Observability Details
- In early baseline tests, an unclipped texture streamer caused private bytes to expand at 14 MB/minute; automated soak tests caught the leak before integration.
- Worst-frame p95 latency settled at 6.71 ms in baseline runs and 7.88 ms under continuous streaming load.
What We Think It Suggests
- Autonomous agent playtesting running continuous multi-kilometer traversals can effectively surface memory leaks and frame budget outliers that short benchmarks miss.
- Maintaining flat memory allocation over extended continuous traversal provides strong operational evidence against uncollected resource leaks.
Limits
- 30-minute soak duration: While sufficient to detect linear memory leaks, long-term 24-hour endurance soaks are needed to identify rare accumulation defects.
- Headless execution: Tested via headless and automated agent navigation; interactive player input variance and erratic camera motions may trigger different rendering paths.
Detailed Analysis & Field Observations
A game engine can run beautifully in a 30-second benchmark run while harboring fatal memory leaks that crash the application after 45 minutes of real gameplay. Streaming open-world terrain, instantiating particle buffers, and unloading texture mipmaps frequently leave behind dangling allocations.
To validate Atlas Engine's real-time presentation pipeline, we created an autonomous playtesting harness. Rather than relying on human QA to wander environments, an automated agent executes continuous navigation routines, streaming assets, navigating terrain elevations, and testing camera frustum boundaries.
In a full 1,800-second (30-minute) continuous traversal soak, the agent traversed 9,595 meters of terrain across 53 distinct streaming regions. The memory telemetry showed resource stability on this run: RSS memory settled at 3,261 MB and private byte allocation was flat (-0.08 MB/min growth rate), confirming zero geometry, texture, or audio buffer leakage over extended play.
Frame pacing remained equally disciplined. Median worst-frame latency settled at 7.88 ms throughout the 30-minute run, comfortably below the 8.33 ms limit required for native 120 fps presentation. Over budget frames accounted for less than 0.9% of all rendered frames.
Automating continuous soak testing transforms performance validation from occasional manual panic checks into a continuous regression gate.