[nfc] api headers benchmark

src/workerd/tests/BUILD.bazel

@@ -48,13 +48,21 @@ wd_cc_benchmark(
 )
 
 wd_cc_benchmark(
-    name = "bench-headers",
-    srcs = ["bench-headers.c++"],
+    name = "bench-kj-headers",
+    srcs = ["bench-kj-headers.c++"],
     deps = [
         "@capnp-cpp//src/kj/compat:kj-http",
     ],
 )
 
+wd_cc_benchmark(
+    name = "bench-api-headers",
+    srcs = ["bench-api-headers.c++"],
+    deps = [
+        ":test-fixture",
+    ],
+)
+
 wd_cc_benchmark(
     name = "bench-global-scope",
     srcs = ["bench-global-scope.c++"],

src/workerd/tests/bench-api-headers.c++

@@ -0,0 +1,61 @@
+// Copyright (c) 2023 Cloudflare, Inc.
+// Licensed under the Apache 2.0 license found in the LICENSE file or at:
+//     https://opensource.org/licenses/Apache-2.0
+
+#include <workerd/tests/bench-tools.h>
+#include <workerd/tests/test-fixture.h>
+#include <workerd/api/http.h>
+
+// A benchmark for js Header class.
+
+namespace workerd {
+namespace {
+
+struct ApiHeaders: public benchmark::Fixture {
+  virtual ~ApiHeaders() noexcept(true) {}
+
+
+  void SetUp(benchmark::State& state) noexcept(true) override {
+    fixture = kj::heap<TestFixture>();
+
+    kj::HttpHeaderTable::Builder builder;
+    builder.add("Host");
+    builder.add("Accept");
+    builder.add("Content-Type");
+    builder.add("Last-Modified");
+    table = builder.build();
+    kjHeaders = kj::heap<kj::HttpHeaders>(*table);
+    auto in = kj::heapString(
+          "GET /favicon.ico HTTP/1.1\r\n"
+          "Host: 0.0.0.0=5000\r\n"
+          "User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9) Gecko/2008061015 Firefox/3.0\r\n"
+          "Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8\r\n"
+          "Accept-Language: en-us,en;q=0.5\r\n"
+          "Accept-Encoding: gzip,deflate\r\n"
+          "Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7\r\n"
+          "Keep-Alive: 300\r\n"
+          "Connection: keep-alive\r\n"
+          "\r\n");
+    KJ_EXPECT(kjHeaders->tryParseRequest(in.asArray()).is<kj::HttpHeaders::Request>());
+  }
+
+  void TearDown(benchmark::State& state) noexcept(true) override {
+    fixture = nullptr;
+  }
+
+  kj::Own<TestFixture> fixture;
+  kj::Own<kj::HttpHeaderTable> table;
+  kj::Own<kj::HttpHeaders> kjHeaders;
+};
+
+// initialization performs a lot of copying, benchmark it
+BENCHMARK_F(ApiHeaders, constructor)(benchmark::State& state) {
+  fixture->runInIoContext([&](const TestFixture::Environment& env) {
+    for (auto _ : state) {
+      auto jsHeaders = jsg::alloc<api::Headers>(*kjHeaders, api::Headers::Guard::REQUEST);
+    }
+  });
+}
+
+} // namespace
+} // namespace workerd

src/workerd/tests/bench-headers.c++ → src/workerd/tests/bench-kj-headers.c++

@@ -8,8 +8,8 @@
 namespace workerd {
 namespace {
 
-struct Fixture: public benchmark::Fixture {
-  virtual ~Fixture() noexcept(true) {}
+struct KjHeaders: public benchmark::Fixture {
+  virtual ~KjHeaders() noexcept(true) {}
 
   void SetUp(benchmark::State& state) noexcept(true) override {
     kj::HttpHeaderTable::Builder builder;
@@ -23,7 +23,7 @@ struct Fixture: public benchmark::Fixture {
   kj::Own<kj::HttpHeaderTable> table;
 };
 
-BENCHMARK_F(Fixture, Parse)(benchmark::State& state) {
+BENCHMARK_F(KjHeaders, Parse)(benchmark::State& state) {
   for (auto _ : state) {
     kj::HttpHeaders headers(*table);