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

Compiling oxlint in release mode with debug information

For profiling, you will need to compile the oxlint binary in release mode with debug information enabled. You can do that by passing --profile release-with-debug to cargo build:

cargo build --profile release-with-debug --bin oxlint

After building, the binary is located at ./target/release-with-debug/oxlint. This is the binary that should be used for profiling.

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.

To use Samply with oxlint, run samply record followed by the oxlint command and arguments:

samply record ./target/release-with-debug/oxlint .

To improve the profiling experience, you might consider some of the following options:

• oxlint: --silent will suppress diagnostics output and keep the profile more focused.
• oxlint: --threads 1 will run the linter single threaded, which is slower, but makes it easier to analyze the profile for single-threaded performance.
• samply record: --rate <number> will sample the profile at a higher rate. The default is 1000Hz (1ms), but increasing this will provide more detailed information at the cost of a larger profile file.

For example, running oxlint single-threaded with a 0.1ms sample rate:

samply record --rate 10000 ./target/release-with-debug/oxlint --silent --threads 1 .

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

Then, if you haven't already, ensure that the oxlint binary is compiled.

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-with-debug/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'.