horizon-airdef/docs/core-performance.md

Core performance comparison

core-performance adds the pinned core performance mods while retaining the baseline's 12 full-detail chunks, 12 simulation chunks, suggested heap, custom graphics preset and OpenGL backend. Neither profile installs distant terrain or Iris shaders; every original experimental controller is disabled. Use this pair for the first comparison at the same view distance, then test balanced separately for its additional 128-chunk distant horizon.

The loaded-mod report also exposes dependencies bundled inside those downloads, such as Transition and Trender in this observed core run. The comparator treats these software changes as explicit experiment variables. Matching configuration is not proof of pixel-identical rendering or exhaustive gameplay equivalence.

The selected 4 October 2026 live observations use separate private world copies, a stationary camera, native Linux x64 Java 25, G1, compact headers and the same 3 GiB maximum heap. The test copies use Peaceful difficulty and a noon clock with weather/time advancement disabled to reduce lighting variation. Distributed packs do not change world rules. First saved cameras and saved clock/rules are checked. JFR begins roughly 121 seconds after demo dismissal; a separate 120-second frame capture begins roughly 307 seconds after dismissal.

Observation	Vanilla baseline	Core mods
Eligible frames	651	785
Average frame rate	5.44 FPS	6.56 FPS
95th-percentile frame interval	194.89 ms	163.18 ms
Sampled peak process RSS	2,710.76 MiB	2,108.96 MiB
Average process CPU	2.81 cores	2.88 cores
Tick execution mean	8.98 ms	6.37 ms
Recorded tick samples	2,401	2,402

In this single fixed-order, software-rendered pair, average FPS is about 20.7% higher and sampled peak RSS about 22.2% lower with the core stack. Process CPU is slightly higher while more frames are rendered. Tick execution durations are lower; their inverse is execution capacity, not observed TPS. Both captures span about 120 seconds and record approximately 20 tick samples per elapsed second. These are descriptive observations, not a statistical or universal speedup claim. They do not isolate which mod caused a difference. Entity activity, completion of rendering work, cache/JIT and thermal state remain possible variables. RSS excludes a complete GPU/unified-memory measurement; Apple Silicon performance remains unmeasured. Hardware graphics and repeated alternating trials are needed.

Preceding JFR counter rates for the server and render thread are lower with the core stack, but total and longest measured GC pauses are higher in that profile. Those recordings precede the frame captures, so rates/pauses must not be treated as if they covered the later frame interval. Selected observations retain both findings instead of presenting only favorable measurements.

The selected raw observations retain software identity, protocol and both positive and negative measurements. Both clients save and exit with code zero; the core world reloads and saves again. Actual JSON/CSV viewer and mobile checks pass. Windows, macOS ARM and Linux builds pass, with byte-identical local and independent Linux production JARs. These are platform build checks, not game graphics tests on each platform.