DioCrafts
78 lines
2.6 KiB
Markdown
78 lines
2.6 KiB
Markdown
# Link Time Optimization (LTO) in OxiCloud
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## Overview
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OxiCloud uses Link Time Optimization (LTO) to significantly improve runtime performance. LTO is a technique that allows the compiler to perform optimizations across module boundaries during the linking phase, which can lead to better inlining, dead code elimination, and overall more efficient binaries.
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## Implemented Optimizations
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This project uses the following optimization settings:
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### Release Profile
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```toml
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[profile.release]
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lto = "fat" # Full cross-module optimization
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codegen-units = 1 # Maximum optimization but slower compile time
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opt-level = 3 # Maximum optimization level
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panic = "abort" # Smaller binary size by removing panic unwinding
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strip = true # Removes debug symbols for smaller binary
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```
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### Development Profile
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```toml
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[profile.dev]
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opt-level = 1 # Light optimization for faster build time
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debug = true # Keep debug information for development
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```
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### Benchmark Profile
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```toml
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[profile.bench]
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lto = "fat" # Full optimization for benchmarks
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codegen-units = 1 # Maximum optimization
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opt-level = 3 # Maximum optimization level
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```
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## Performance Improvements
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The optimizations typically result in:
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1. **Smaller binary size**: Removing unused code and metadata
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2. **Faster execution**: Better inlining and code optimizations
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3. **Reduced memory usage**: More efficient code layout and execution
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## LTO Options Explained
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- **fat**: Also known as "full" LTO, performs optimizations across all crate boundaries. Maximum optimization but longest compile time.
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- **thin**: A faster version of LTO that trades some optimization for compile speed. Good for development.
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- **off**: No cross-module optimization.
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## Build Time Impact
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While LTO provides runtime performance benefits, it increases compilation time. For OxiCloud, we chose:
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- Development builds: Minimal LTO (`opt-level = 1`) for faster iteration
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- Release builds: Full LTO for maximum end-user performance
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- Benchmark builds: Full LTO to measure actual optimized performance
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## Measuring the Impact
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To measure the impact of these optimizations, run our benchmarks:
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```bash
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# Run benchmarks with all optimizations
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cargo bench
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# Compare with non-optimized build (remove for comparison only)
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RUSTFLAGS="-C lto=off" cargo bench
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```
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## When to Adjust Settings
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Consider adjusting these settings if:
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1. You need faster compile times during development
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2. You're experiencing unexpected runtime behavior
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3. You want to experiment with optimization/binary size tradeoffs
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For most users, the default settings should provide a good balance of performance and usability. |