Loading the eight carried-over mods in the game (not only the probe) showed
two limits real packs reach. Block textures past 2048 layers are another PR;
this one handles block states and measures a pack.
- Chunk sections store a block state in 16 bits. Vanilla 26.3 has 35,723
states; Macaw's four mods add 36,154, the eight 41,389. Past 65,536 ids
wrapped onto other blocks (a trapdoor became a hanging sign).
mod_content::build now refuses a set of mods past MAX_STATES and names the
states per mod; the game then starts without content mods, as for any
refused content.
- tools/mod_port_harness.py probes each mod on its own against vanilla, as a
player adding it would load it.
- tools/perf_bench.py --game neoforge: Minecraft 1.21.1 on NeoForge 21.1.259
with --mod-jars and --deps, driven by a dev-only NeoForge port of the bench
mod (mods/horizon/src/neoforge-bench); --port-work loads a work folder's
carried-over mods into Horizon. tools/neoforge_oracle.py installs the
client once under .local/neoforge-oracle (the installer, then the vanilla
libraries it inherits, sha1-checked) and builds the driver. A NeoForge
start that crashes before the driver loads (FML reading fml.toml while
creating it) is retried once.
Measured (docs/modpacks.md): six ported mods in Horizon against the same
mods on NeoForge, Mac mini M4 Pro, 2 games per row on a loaded machine. The
world is ready 3.1x sooner at 8 and 16 chunks, the flights run 1.7x and
3.6x the frames, and Horizon's RSS is not lower (+1.1 GB with the mods).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Builds that report status.streaming are loaded once chunk counts are
stable and no stage (generation, decoration, light, meshing) has held work
for half a second. Meshing going quiet also waited through the remeshing
that follows a load (fluids settling, random ticks: 1500 falling to 60
meshes/s for ~150 s at RD16), which is simulation, not loading. Older
builds keep the meshing-rate rule.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Sections wait for their neighbours' light before they are meshed, so the
chunk counts settled while edge sections were still undrawn.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Each game runs --repeats times (3) per render distance and writes one v1
report per distance (benchmarks/perf/<label>-rd<N>.json): figures as means
with standard deviation and 95% CI, per-flight frame entries with the fixed
histogram, the hardware without the host name. frames() and summary() match
crates/horizon-bench value for value (tested on the same inputs).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
tools/perf_bench.py runs Horizon, the vanilla 26.3 client and vanilla with
Sodium, Lithium, FerriteCore and ImmediatelyFast through the same steps:
fresh world (seed 1234, creative) per render distance, start to title, start
to in-world, then per scene teleport, chunk load, settle and a fixed 192-block
flight. Every frame time is kept and one function computes average FPS, 1% and
0.1% lows, p50/p95/p99/p99.9 and a frame-time histogram for every game; RSS is
sampled from outside the process for every game. One options.txt (vanilla's
keys, Fancy preset values with a Custom preset so the render distance holds)
is written for all of them.
Vanilla is driven by a dev-only Fabric mod (mods/horizon/src/bench) compiled
against the user's own client jar: it creates the world with
WorldOpenFlows.createFreshLevel, teleports with /tp and places the player on
the path every frame as horizon-ctl fly does. Nothing of the game is
redistributed and the performance mods are fetched from Modrinth with the
hashes pinned in packs/mods.lock.json.
Horizon side: `fly ... PITCH raw` also replies with every frame time, and
--offscreen drives frames from the event loop, so a window nobody sees (a
locked macOS session) still renders.
docs/benchmark.md describes what is measured, how fairness is kept, the
caveats and how to reproduce it.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Ludovic Marie