Binary Size Reduction

[kioku]

Current State

• Release binary: 8.4MB
• Debug binary: 26MB

Optimization Strategy

1. Compiler Optimizations (Quick Win - ~2-3MB reduction)

Add to Cargo.toml:

[profile.release]
strip = true          # Strip symbols
opt-level = "z"       # Optimize for size over speed
lto = "fat"          # Link-time optimization
codegen-units = 1    # Single codegen unit
panic = "abort"      # Smaller panic handler

2. Code-level Optimizations (~500KB-1MB)

Remove Unused Code:

• Audit openapiv3 usage - might be pulling in unnecessary schemas
• Check if all error variants are needed (40+ variants)
• Remove debug/tracing code in release builds

String Optimization:

• Use &'static str where possible instead of String
• Consider string interning for repeated strings
• Reduce string allocations in hot paths

Reduce Monomorphization:

• Use dynamic dispatch (Box<dyn Error>) instead of generics where performance isn't critical
• Combine generic functions that generate duplicate code

3. Alternative Build Strategies

Custom Build Profiles:

[profile.minimal]
inherits = "release"
opt-level = "z"
strip = true
lto = true
codegen-units = 1
panic = "abort"

[profile.size-optimized]
inherits = "release" 
opt-level = "s"      # Balance size/speed
strip = true
lto = "thin"         # Faster LTO
codegen-units = 1

Build commands:

# Smallest possible binary
cargo build --profile minimal

# Balanced size/performance
cargo build --profile size-optimized

Additional Cargo flags:

# Further size reduction
CARGO_PROFILE_RELEASE_OPT_LEVEL=z \
CARGO_PROFILE_RELEASE_LTO=fat \
CARGO_PROFILE_RELEASE_CODEGEN_UNITS=1 \
cargo build --release

# Use nightly for additional optimizations
cargo +nightly build -Z build-std=std,panic_abort \
  -Z build-std-features=panic_immediate_abort --release

Measurement Plan

Track binary size with:

# Check size
ls -lh target/release/aperture

# Analyze what's taking space (requires cargo-bloat)
cargo install cargo-bloat
cargo bloat --release --crates

# Check symbol sizes
nm -S target/release/aperture | sort -k2 -nr | head -20

Expected Results

• Compiler optimizations alone: 8.4MB → 5.5-6MB
• With code optimizations: 5-5.5MB
• With nightly + build-std: Potentially <5MB

Trade-offs

• opt-level = "z": ~10-20% slower execution
• lto = "fat": Longer compile times (+30-60s)
• panic = "abort": No stack unwinding on panic
• Code optimizations: More complex code in some cases

Success Criteria

• Binary < 6MB with standard release profile
• Binary < 5.5MB with minimal profile
• No functionality regression
• Document size impact of different profiles