diff --git a/modules/caddyhttp/caddyhttp.go b/modules/caddyhttp/caddyhttp.go
index aacafc92e..761c37a54 100644
--- a/modules/caddyhttp/caddyhttp.go
+++ b/modules/caddyhttp/caddyhttp.go
@@ -286,6 +286,7 @@ func CleanPath(p string, collapseSlashes bool) string {
 	// and then remove the remaining temporary characters.
 	const tmpCh = 0xff
 	var sb strings.Builder
+	sb.Grow(len(p) + 1)
 	for i, ch := range p {
 		if ch == '/' && i > 0 && p[i-1] == '/' {
 			sb.WriteByte(tmpCh)
diff --git a/modules/caddyhttp/caddyhttp_bench_test.go b/modules/caddyhttp/caddyhttp_bench_test.go
new file mode 100644
index 000000000..213b3ae05
--- /dev/null
+++ b/modules/caddyhttp/caddyhttp_bench_test.go
@@ -0,0 +1,25 @@
+// Copyright 2015 Matthew Holt and The Caddy Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package caddyhttp
+
+import "testing"
+
+func BenchmarkCleanPathNoCollapse(b *testing.B) {
+	const p = "/foo/bar/baz/qux/some/longer/path/segment/here/index.html"
+	b.ReportAllocs()
+	for b.Loop() {
+		_ = CleanPath(p, false)
+	}
+}
diff --git a/modules/caddyhttp/headers/headers.go b/modules/caddyhttp/headers/headers.go
index a1afaa548..1c396b799 100644
--- a/modules/caddyhttp/headers/headers.go
+++ b/modules/caddyhttp/headers/headers.go
@@ -259,11 +259,9 @@ func (ops *HeaderOps) ApplyTo(hdr http.Header, repl *caddy.Replacer) {
 		if expanded := repl.ReplaceKnown(fieldName, ""); expanded != fieldName {
 			fieldName = http.CanonicalHeaderKey(expanded)
 		}
-		var newVals []string
+		newVals := make([]string, len(vals))
 		for i := range vals {
-			// append to new slice so we don't overwrite
-			// the original values in ops.Set
-			newVals = append(newVals, repl.ReplaceKnown(vals[i], ""))
+			newVals[i] = repl.ReplaceKnown(vals[i], "")
 		}
 		if fieldName == "Set-Cookie" && len(newVals) > 1 {
 			hdr.Del(fieldName)
diff --git a/modules/caddyhttp/headers/headers_bench_test.go b/modules/caddyhttp/headers/headers_bench_test.go
new file mode 100644
index 000000000..e75ca6b46
--- /dev/null
+++ b/modules/caddyhttp/headers/headers_bench_test.go
@@ -0,0 +1,38 @@
+// Copyright 2015 Matthew Holt and The Caddy Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package headers
+
+import (
+	"net/http"
+	"testing"
+
+	"github.com/caddyserver/caddy/v2"
+)
+
+func BenchmarkHeaderOpsApplyToSet(b *testing.B) {
+	ops := &HeaderOps{
+		Set: http.Header{
+			"Content-Type":    []string{"text/html; charset=utf-8"},
+			"Cache-Control":   []string{"public", "max-age=3600", "immutable"},
+			"X-Custom-Header": []string{"value-one", "value-two"},
+		},
+	}
+	repl := caddy.NewReplacer()
+	b.ReportAllocs()
+	for b.Loop() {
+		hdr := make(http.Header)
+		ops.ApplyTo(hdr, repl)
+	}
+}
diff --git a/modules/caddyhttp/matchers.go b/modules/caddyhttp/matchers.go
index 89452b24d..a53c5bdb5 100644
--- a/modules/caddyhttp/matchers.go
+++ b/modules/caddyhttp/matchers.go
@@ -552,6 +552,7 @@ func (MatchPath) matchPatternWithEscapeSequence(escapedPath, matchPath string) b
 	// of the path, then switching to the escaped parts where
 	// the pattern hints to us wherever % is present.
 	var sb strings.Builder
+	sb.Grow(len(escapedPath))
 
 	// iterate the pattern and escaped path in lock-step;
 	// increment iPattern every time we consume a char from the pattern,
diff --git a/modules/caddyhttp/reverseproxy/selectionpolicies.go b/modules/caddyhttp/reverseproxy/selectionpolicies.go
index 431a2fde0..20276bec9 100644
--- a/modules/caddyhttp/reverseproxy/selectionpolicies.go
+++ b/modules/caddyhttp/reverseproxy/selectionpolicies.go
@@ -152,7 +152,7 @@ func (r *WeightedRoundRobinSelection) Select(pool UpstreamPool, _ *http.Request,
 		return pool[0]
 	}
 	var index, totalWeight int
-	var weights []int
+	weights := make([]int, 0, len(r.Weights))
 
 	for _, w := range r.Weights {
 		if w > 0 {
diff --git a/modules/caddyhttp/reverseproxy/selectionpolicies_bench_test.go b/modules/caddyhttp/reverseproxy/selectionpolicies_bench_test.go
new file mode 100644
index 000000000..15d1c16cf
--- /dev/null
+++ b/modules/caddyhttp/reverseproxy/selectionpolicies_bench_test.go
@@ -0,0 +1,39 @@
+// Copyright 2015 Matthew Holt and The Caddy Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package reverseproxy
+
+import (
+	"net/http"
+	"testing"
+)
+
+func BenchmarkWeightedRoundRobinSelect(b *testing.B) {
+	pool := UpstreamPool{
+		{Host: new(Host), Dial: "0.0.0.1"},
+		{Host: new(Host), Dial: "0.0.0.2"},
+		{Host: new(Host), Dial: "0.0.0.3"},
+		{Host: new(Host), Dial: "0.0.0.4"},
+		{Host: new(Host), Dial: "0.0.0.5"},
+	}
+	wrrPolicy := &WeightedRoundRobinSelection{
+		Weights:     []int{5, 4, 3, 2, 1},
+		totalWeight: 15,
+	}
+	req, _ := http.NewRequest("GET", "/", nil)
+	b.ReportAllocs()
+	for b.Loop() {
+		_ = wrrPolicy.Select(pool, req, nil)
+	}
+}
diff --git a/modules/caddyhttp/rewrite/rewrite.go b/modules/caddyhttp/rewrite/rewrite.go
index c463fe254..df5d32369 100644
--- a/modules/caddyhttp/rewrite/rewrite.go
+++ b/modules/caddyhttp/rewrite/rewrite.go
@@ -374,6 +374,7 @@ func escapePathPreservingSlashes(path string) string {
 // duplicate keys rather than replaces.
 func buildQueryString(qs string, repl *caddy.Replacer) string {
 	var sb strings.Builder
+	sb.Grow(len(qs))
 
 	// first component must be key, which is the same
 	// as if we just wrote a value in previous iteration
diff --git a/modules/caddyhttp/rewrite/rewrite_bench_test.go b/modules/caddyhttp/rewrite/rewrite_bench_test.go
new file mode 100644
index 000000000..d13af82be
--- /dev/null
+++ b/modules/caddyhttp/rewrite/rewrite_bench_test.go
@@ -0,0 +1,30 @@
+// Copyright 2015 Matthew Holt and The Caddy Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package rewrite
+
+import (
+	"testing"
+
+	"github.com/caddyserver/caddy/v2"
+)
+
+func BenchmarkBuildQueryString(b *testing.B) {
+	repl := caddy.NewReplacer()
+	const qs = "foo=bar&baz=qux&search=hello+world&page=2&sort=desc&filter=active&id=12345"
+	b.ReportAllocs()
+	for b.Loop() {
+		_ = buildQueryString(qs, repl)
+	}
+}