marginally optimize txnToDigest a bit

algorand · Nov 8, 2023 · 8c4c28b · 8c4c28b
1 parent 5fc75b6
commit 8c4c28b
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Showing 2 changed files with 51 additions and 10 deletions.
diff --git a/data/appRateLimiter.go b/data/appRateLimiter.go
@@ -248,16 +248,19 @@ func txgroupToKeys(txgroup []transactions.SignedTxn, origin []byte, seed uint64,
 	// The 16 bytes salt makes it harder to find collisions if an adversary attempts to censor
 	// some app by finding a collision with some app and flood a network with such transactions:
 	// h(app + relay_ip) = h(app2 + relay_ip).
-	var buf [8 + 16 + 16]byte // uint64 + 16 bytes of salt + up to 16 bytes of address
-	txnToDigest := func(appIdx basics.AppIndex) keyType {
-		binary.LittleEndian.PutUint64(buf[:8], uint64(appIdx))
-		copy(buf[8:], salt[:])
-		copied := copy(buf[8+16:], origin)
 
-		h := blake2b.Sum256(buf[:8+16+copied])
-		var key keyType
-		copy(key[:], h[:len(key)])
-		return key
+	// uint64 + 16 bytes of salt + up to 16 bytes of address
+	// salt and origin are fixed so pre-copy them into the buf
+	var buf [8 + 16 + 16]byte
+	copy(buf[8:], salt[:])
+	copied := copy(buf[8+16:], origin)
+	bufLen := 8 + 16 + copied
+
+	txnToDigest := func(appIdx basics.AppIndex) (key keyType) {
+		binary.LittleEndian.PutUint64(buf[:8], uint64(appIdx))
+		h := blake2b.Sum256(buf[:bufLen])
+		copy(key[:], h[:len(keyType{})])
+		return
 	}
 	txnToBucket := func(appIdx basics.AppIndex) int {
 		return int(memhash64(uint64(appIdx), seed) % uint64(numBuckets))
@@ -283,9 +286,9 @@ func txgroupToKeys(txgroup []transactions.SignedTxn, origin []byte, seed uint64,
 			if len(txgroup[i].Txn.ForeignApps) > 0 {
 				for _, appIdx := range txgroup[i].Txn.ForeignApps {
 					if valid(appIdx) {
-						seen[appIdx] = struct{}{}
 						keysBuckets.buckets = append(keysBuckets.buckets, txnToBucket(appIdx))
 						keysBuckets.keys = append(keysBuckets.keys, txnToDigest(appIdx))
+						seen[appIdx] = struct{}{}
 					}
 				}
 			}

diff --git a/data/appRateLimiter_test.go b/data/appRateLimiter_test.go
@@ -486,3 +486,41 @@ func TestAppRateLimiter_TxgroupToKeys(t *testing.T) {
 	require.Equal(t, len(kb.buckets), len(kb.buckets))
 	putAppKeyBuf(kb)
 }
+
+func BenchmarkAppRateLimiter_TxgroupToKeys(b *testing.B) {
+	rnd := rand.New(rand.NewSource(123))
+
+	txgroups := make([][]transactions.SignedTxn, 0, b.N)
+	for i := 0; i < b.N; i++ {
+		txgroup := make([]transactions.SignedTxn, 0, config.MaxTxGroupSize)
+		for j := 0; j < config.MaxTxGroupSize; j++ {
+			apptxn := transactions.Transaction{
+				Type: protocol.ApplicationCallTx,
+				ApplicationCallTxnFields: transactions.ApplicationCallTxnFields{
+					ApplicationID: basics.AppIndex(rnd.Uint64()),
+					ForeignApps:   []basics.AppIndex{basics.AppIndex(rnd.Uint64()), basics.AppIndex(rnd.Uint64()), basics.AppIndex(rnd.Uint64()), basics.AppIndex(rnd.Uint64())},
+				},
+			}
+			txgroup = append(txgroup, transactions.SignedTxn{Txn: apptxn})
+		}
+		txgroups = append(txgroups, txgroup)
+	}
+
+	b.ResetTimer()
+	b.ReportAllocs()
+
+	origin := make([]byte, 4)
+	_, err := rnd.Read(origin)
+	require.NoError(b, err)
+	require.NotEmpty(b, origin)
+
+	salt := [16]byte{}
+	_, err = rnd.Read(salt[:])
+	require.NoError(b, err)
+	require.NotEmpty(b, salt)
+
+	for i := 0; i < b.N; i++ {
+		kb := txgroupToKeys(txgroups[i], origin, 123, salt, numBuckets)
+		putAppKeyBuf(kb)
+	}
+}