1 files changed, 77 insertions, 0 deletions
diff --git a/gopls/internal/regtest/bench/iwl_test.go b/gopls/internal/regtest/bench/iwl_test.go
new file mode 100644
index 000000000..352078e7f
--- /dev/null
+++ b/gopls/internal/regtest/bench/iwl_test.go
@@ -0,0 +1,77 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package bench
+
+import (
+	"testing"
+
+	"golang.org/x/tools/gopls/internal/lsp/command"
+	"golang.org/x/tools/gopls/internal/lsp/fake"
+	"golang.org/x/tools/gopls/internal/lsp/protocol"
+	. "golang.org/x/tools/gopls/internal/lsp/regtest"
+)
+
+// BenchmarkInitialWorkspaceLoad benchmarks the initial workspace load time for
+// a new editing session.
+func BenchmarkInitialWorkspaceLoad(b *testing.B) {
+	if testing.Short() {
+		// TODO(rfindley): remove this skip once the released gopls version
+		// supports the memstats command.
+		b.Skip("temporarily skipping as baseline gopls versions do not support the memstats command")
+	}
+	tests := []struct {
+		repo string
+		file string
+	}{
+		{"tools", "internal/lsp/cache/snapshot.go"},
+		{"kubernetes", "pkg/controller/lookup_cache.go"},
+		{"pkgsite", "internal/frontend/server.go"},
+		{"starlark", "starlark/eval.go"},
+		{"istio", "pkg/fuzz/util.go"},
+		{"kuma", "api/generic/insights.go"},
+	}
+
+	for _, test := range tests {
+		b.Run(test.repo, func(b *testing.B) {
+			repo := getRepo(b, test.repo)
+			// get the (initialized) shared env to ensure the cache is warm.
+			// Reuse its GOPATH so that we get cache hits for things in the module
+			// cache.
+			sharedEnv := repo.sharedEnv(b)
+			b.ResetTimer()
+
+			for i := 0; i < b.N; i++ {
+				doIWL(b, sharedEnv.Sandbox.GOPATH(), repo, test.file)
+			}
+		})
+	}
+}
+
+func doIWL(b *testing.B, gopath string, repo *repo, file string) {
+	// Exclude the time to set up the env from the benchmark time, as this may
+	// involve installing gopls and/or checking out the repo dir.
+	b.StopTimer()
+	config := fake.EditorConfig{Env: map[string]string{"GOPATH": gopath}}
+	env := repo.newEnv(b, "iwl."+repo.name, config)
+	defer env.Close()
+	b.StartTimer()
+
+	// Open an arbitrary file to ensure that gopls starts working.
+	//
+	// In the future, this may matter if gopls doesn't eagerly construct
+	// the workspace.
+	env.OpenFile(file)
+
+	env.Await(InitialWorkspaceLoad)
+	b.StopTimer()
+	params := &protocol.ExecuteCommandParams{
+		Command: command.MemStats.ID(),
+	}
+	var memstats command.MemStatsResult
+	env.ExecuteCommand(params, &memstats)
+	b.ReportMetric(float64(memstats.HeapAlloc), "alloc_bytes")
+	b.ReportMetric(float64(memstats.HeapInUse), "in_use_bytes")
+	b.StartTimer()
+}