Performance

• All performance issues (runtime and compilation speed) are considered as bugs in this project.
• Follow guidance from the Rust performance book.

Compile Time

While Rust has gained a reputation for its comparatively slower compilation speed, we have dedicated significant effort to fine-tune the Rust compilation speed.

Our goal is to minimize any impact on development workflow, ensuring that Oxc based tools remain fast to compile.

Our CI runs complete in 3 minutes, any regressions need to be fixed.

Profile

Heap Allocation

Try dhat.

CPU - Samply

Samply is a command line CPU profiler which uses the Firefox profiler as its UI. Works on macOS and Linux.

CPU - Mac Xcode Instruments

cargo instruments is the tool of choice to bridge Mac Xcode instruments.

The following instruction replicates the procedure of cargo instruments.

First, install Xcode Instruments command-line tools:

xcode-select --install

And then change the build profile to show debug symbols:

[profile.release]
debug = true # enable debug symbols
strip = false # do not strip symbols

Build the binary with --release:

cargo build --release --bin oxlint --features allocator

Once the project is built, the binary is located at ./target/release/oxlint.

Under the hood, cargo instruments invokes the xcrun xctrace command, which is equivalent to

xcrun xctrace record --template 'Time Profile' --output . --launch -- /path/to/oxc/target/release/oxlint

Running the command above produces the following output

Starting recording with the Time Profiler template. Launching process: oxlint.
Ctrl-C to stop the recording
Target app exited, ending recording...
Recording completed. Saving output file...
Output file saved as: Launch_oxlint_2023-09-03_4.41.45 PM_EB179B85.trace

Open the trace file open Launch_oxlint_2023-09-03_4.41.45\ PM_EB179B85.trace.

To see a top down trace:

1. On the top panel, click CPUs
2. On the left input box, click x then select Time Profiler
3. At the bottom panel, click "Call Tree", turn on "Invert Call Tree" and turn off separate by thread.

For memory and disk operations, use --template 'Allocations' and --template 'File Activity'.