add benchmarks

http/httphi/bench_test.go

@@ -0,0 +1,89 @@
+package httphi
+
+import (
+	"io"
+	"testing"
+)
+
+// benchConn replays a fixed request and discards the response. It allocates
+// nothing itself so benchmark alloc counts belong to the package under test.
+type benchConn struct {
+	request string
+	read    int
+	written int
+}
+
+func (c *benchConn) rewind() { c.read, c.written = 0, 0 }
+
+func (c *benchConn) Read(b []byte) (int, error) {
+	if c.read >= len(c.request) {
+		return 0, io.EOF
+	}
+	n := copy(b, c.request[c.read:])
+	c.read += n
+	return n, nil
+}
+
+func (c *benchConn) Write(b []byte) (int, error) {
+	c.written += len(b)
+	return len(b), nil
+}
+
+func (c *benchConn) Close() error { return nil }
+
+// benchBody is package level: converting a string literal to []byte inside the
+// handler would allocate on every request and hide the router's own cost.
+var benchBody = []byte("hello world")
+
+func benchExchange(b *testing.B, conn conn) *Exchange {
+	b.Helper()
+	const bufferSize = 1024
+	exch := new(Exchange)
+	exch.Configure(make([]byte, 2*bufferSize), bufferSize, false)
+	if !exch.Acquire(conn) {
+		b.Fatal("fresh exchange failed to acquire connection")
+	}
+	return exch
+}
+
+// BenchmarkHandle measures a whole exchange: read, parse, mux and respond.
+func BenchmarkHandle(b *testing.B) {
+	for _, bb := range []struct {
+		name    string
+		request string
+		handler HandlerFunc
+	}{
+		{
+			name:    "GETWithHeaders",
+			request: "GET / HTTP/1.1\r\nHost: tinygo.org\r\nUser-Agent: bench\r\nAccept: */*\r\nConnection: close\r\n\r\n",
+			handler: func(ex *Exchange) {
+				ex.SetHeader("Content-Type", "text/plain")
+				ex.SetHeaderInt("Content-Length", int64(len(benchBody)), 10)
+				ex.Write(benchBody)
+			},
+		},
+		{
+			name:    "NotFound",
+			request: "GET /nowhere HTTP/1.1\r\nHost: tinygo.org\r\n\r\n",
+			handler: nil, // Unregistered: exercises the 404 path.
+		},
+	} {
+		b.Run(bb.name, func(b *testing.B) {
+			var mux MuxSlice
+			if bb.handler != nil {
+				mux.Handle("GET /", bb.handler)
+			}
+			conn := &benchConn{request: bb.request}
+			exch := benchExchange(b, conn)
+			b.ReportAllocs()
+			b.SetBytes(int64(len(bb.request)))
+			b.ResetTimer()
+			for b.Loop() {
+				conn.rewind()
+				exch.Release()
+				exch.Acquire(conn)
+				Handle(exch, &mux, nopBackoff)
+			}
+		})
+	}
+}