bench

Documentation

Overview

The bench package implements benchmarks for various LSP operations.

Benchmarks check out specific commits of popular and/or exemplary repositories, and script an external gopls process via a fake text editor. By default, benchmarks run the test executable as gopls (using a special "gopls mode" environment variable). A different gopls binary may be used by setting the -gopls_path or -gopls_commit flags.

This package is a work in progress.

Profiling

Benchmark functions run gopls in a separate process, which means the normal test flags for profiling aren't useful. Instead the -gopls_cpuprofile, -gopls_memprofile, -gopls_allocprofile, -gopls_blockprofile, and -gopls_trace flags may be used to pass through profiling to the gopls subproces.

Each of these flags sets a suffix for the respective gopls profile, which is named according to the schema <repo>.<operation>.<suffix>. For example, setting -gopls_cpuprofile=cpu will result in profiles named tools.iwl.cpu, tools.rename.cpu, etc. In some cases, these profiles are for the entire gopls subprocess (as in the initial workspace load), whereas in others they span only the critical section of the benchmark. It is up to each benchmark to implement profiling as appropriate.

Integration with perf.golang.org

Benchmarks that run with -short are automatically tracked by perf.golang.org, at https://perf.golang.org/dashboard/?benchmark=all&repository=tools&branch=release-branch.go1.20

TODO

• add more benchmarks, and more repositories
• fix the perf dashboard to not require the branch= parameter
• improve this documentation