Benchmark for cipher init.

shadowsocks/encrypt.go

@@ -99,7 +99,7 @@ type cipherInfo struct {
 // instead of cipher.Block, so we need to have the following adapter
 // functions.
 // The specific cipher types makes it possible to use Copy to optimize cipher
-// initialization, but do this AFTER evaluation.
+// initialization.
 
 func newBlowFishCipher(key []byte) (cipher.Block, error) {
 	return blowfish.NewCipher(key)
@@ -200,6 +200,16 @@ func (c *Cipher) Copy() *Cipher {
 	// This optimization maybe not necessary. But without this function, we
 	// need to maintain a table cache for newTableCipher and use lock to
 	// protect concurrent access to that cache.
+
+	// AES and DES ciphers does not return specific types, so it's difficult
+	// to create copy. But their initizliation time is less than 4000ns on my
+	// 2.26 GHz Intel Core 2 Duo processor. So no need to worry.
+
+	// Currently, blow-fish and cast5 initialization cost is an order of
+	// maganitude slower than other ciphers. (I'm not sure whether this is
+	// because the current implementation is not highly optimized, or this is
+	// the nature of the algorithm.)
+
 	switch c.enc.(type) {
 	case tableCipher:
 		return c

shadowsocks/encrypt_test.go

@@ -138,3 +138,55 @@ func TestAES256(t *testing.T) {
 func TestDES(t *testing.T) {
 	testBlockCipher(t, "des-cfb")
 }
+
+var cipherKey = make([]byte, 64)
+
+func init() {
+	for i := 0; i < len(cipherKey); i++ {
+		cipherKey[i] = byte(i)
+	}
+}
+
+func BenchmarkRC4Init(b *testing.B) {
+	key := cipherKey[:16]
+	for i := 0; i < b.N; i++ {
+		rc4.NewCipher(key)
+	}
+}
+
+func benchmarkCipherInit(b *testing.B, ci *cipherInfo) {
+	key := cipherKey[:ci.keyLen]
+	for i := 0; i < b.N; i++ {
+		ci.newBlock(key)
+	}
+}
+
+func BenchmarkAES128Init(b *testing.B) {
+	ci := cipherMethod["aes-128-cfb"]
+	benchmarkCipherInit(b, &ci)
+}
+
+func BenchmarkAES192Init(b *testing.B) {
+	ci := cipherMethod["aes-192-cfb"]
+	benchmarkCipherInit(b, &ci)
+}
+
+func BenchmarkAES256Init(b *testing.B) {
+	ci := cipherMethod["aes-256-cfb"]
+	benchmarkCipherInit(b, &ci)
+}
+
+func BenchmarkBlowFishInit(b *testing.B) {
+	ci := cipherMethod["bf-cfb"]
+	benchmarkCipherInit(b, &ci)
+}
+
+func BenchmarkCast5Init(b *testing.B) {
+	ci := cipherMethod["bf-cfb"]
+	benchmarkCipherInit(b, &ci)
+}
+
+func BenchmarkDESInit(b *testing.B) {
+	ci := cipherMethod["des-cfb"]
+	benchmarkCipherInit(b, &ci)
+}