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 - Mac Xcode Instruments

Mac Xcode instruments can be used to produce a CPU profile.

To install Xcode Instruments, install the command-line Tools:

xcode-select --install

For normal Rust builds, cargo instruments can be used as the glue for profiling and creating the trace file.

First, change the profile for showing debug symbols.

[profile.release]
debug = true # debug info with line tables only
strip = false # do not strip symbols

Then build the project

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

The binary is located at ./target/release/oxlint once the project is built.

Under the hood, cargo instruments invokes the xcrun command, equivalent to

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

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.