Rust''s debug profile costs the bench ~45% of solo throughput and ~3x of
p99 latency vs release (267 vs 184 solo calls/sec, p99 5.7 vs 16ms).
Debug disables inlining, runs overflow checks on every arithmetic op,
keeps Future state machines un-collapsed, and lets every Vec allocation
through unoptimized. Other compiled clients in the matrix don''t see
this gap: Go always builds optimized, Python is interpreted, and the
JIT-tiered runtimes (HotSpot for Java, CoreCLR Tier 1 for .NET) close
most of the gap during the warmup window.
The driver now requests `cargo run --release` for Rust and `dotnet run
-c Release --no-build` for .NET, so the two compiled-AOT clients race
under their production-equivalent profiles. Callers must `cargo build
--release -p mxgw-cli` and `dotnet build ... -c Release` once before
running the bench; `--no-build` then keeps each measurement window
free of compilation overhead.
Live re-run (5-way concurrent, 30s, bulkSize 6) after the switch:
rust: 145.35 calls/sec (was 123.26 in debug; 18% gain under contention)
go: 185.59 calls/sec
java: 171.80 calls/sec
dotnet:172.31 calls/sec
python:140.52 calls/sec
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Joseph Doherty
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