perf: RESP & aeloop performance optimization

README.md

@@ -6,7 +6,7 @@ English | [中文](README_CN.md)
 
 ## Introduction
 
-This is rotom, a tiny Redis Server written in Go. It replicates the core event loop mechanism AeLoop in Redis based on I/O multiplexing.
+This is rotom, a high performance, low latency tiny Redis Server written in Go. It replicates the core event loop mechanism AeLoop in Redis based on I/O multiplexing.
 
 ## Features
 

README_CN.md

@@ -6,7 +6,7 @@
 
 ## 介绍
 
-这里是 rotom，一个使用 Go 编写的 tiny Redis Server。基于 IO 多路复用还原了 Redis 中的 AeLoop 核心事件循环机制。
+这里是 rotom，一个使用 Go 编写的高性能，低延迟的 tiny Redis Server。基于 IO 多路复用还原了 Redis 中的 AeLoop 核心事件循环机制。
 
 ## 特性
 

ae.go

@@ -37,6 +37,8 @@ type AeLoop struct {
 	fileEventFd     int
 	timeEventNextId int
 	stop            bool
+
+	_fevents []*AeFileEvent // fes cache
 }
 
 func (loop *AeLoop) AddRead(fd int, proc FileProc, extra interface{}) {
@@ -139,6 +141,7 @@ func AeLoopCreate() (*AeLoop, error) {
 		fileEventFd:     epollFd,
 		timeEventNextId: 1,
 		stop:            false,
+		_fevents:        make([]*AeFileEvent, 128), // pre alloc
 	}, nil
 }
 
@@ -171,7 +174,7 @@ retry:
 	}
 
 	// collect file events
-	fes = make([]*AeFileEvent, 0, n)
+	fes = loop._fevents[:0]
 	for _, ev := range events[:n] {
 		if ev.Events&unix.EPOLLIN != 0 {
 			fe := loop.FileEvents[int(ev.Fd)]

command.go

@@ -1,7 +1,6 @@
 package main
 
 import (
-	"bytes"
 	"fmt"
 	"strconv"
 	"strings"
@@ -13,7 +12,7 @@ import (
 )
 
 var (
-	WITH_SCORES = []byte("WITHSCORES")
+	WITH_SCORES = "WITHSCORES"
 )
 
 type Command struct {
@@ -65,10 +64,6 @@ func equalFold(a, b string) bool {
 	return len(a) == len(b) && strings.EqualFold(a, b)
 }
 
-func equalFoldBytes(a, b []byte) bool {
-	return len(a) == len(b) && bytes.EqualFold(a, b)
-}
-
 func lookupCommand(name string) (*Command, error) {
 	for _, c := range cmdTable {
 		if equalFold(name, c.name) {
@@ -98,11 +93,11 @@ func setCommand(writer *RESPWriter, args []RESP) {
 }
 
 func incrCommand(writer *RESPWriter, args []RESP) {
-	key := args[0].ToString()
+	key := args[0].ToStringUnsafe()
 
 	object, ttl := db.dict.Get(key)
 	if ttl == dict.KEY_NOT_EXIST {
-		db.dict.Set(key, 1)
+		db.dict.Set(strings.Clone(key), 1)
 		writer.WriteInteger(1)
 		return
 	}
@@ -114,6 +109,7 @@ func incrCommand(writer *RESPWriter, args []RESP) {
 		writer.WriteInteger(num)
 
 	case dict.TypeString:
+		// conv to integer
 		bytes := object.Data().([]byte)
 		num, err := RESP(bytes).ToInt()
 		if err != nil {
@@ -345,14 +341,12 @@ func saddCommand(writer *RESPWriter, args []RESP) {
 }
 
 func sremCommand(writer *RESPWriter, args []RESP) {
-	key := args[0].ToString()
-
+	key := args[0].ToStringUnsafe()
 	set, err := fetchSet(key)
 	if err != nil {
 		writer.WriteError(err)
 		return
 	}
-
 	var count int
 	for _, arg := range args[1:] {
 		if set.Remove(arg.ToStringUnsafe()) {
@@ -363,17 +357,15 @@ func sremCommand(writer *RESPWriter, args []RESP) {
 }
 
 func spopCommand(writer *RESPWriter, args []RESP) {
-	key := args[0].ToString()
-
+	key := args[0].ToStringUnsafe()
 	set, err := fetchSet(key)
 	if err != nil {
 		writer.WriteError(err)
 		return
 	}
-
-	item, ok := set.Pop()
+	member, ok := set.Pop()
 	if ok {
-		writer.WriteBulkString(item)
+		writer.WriteBulkString(member)
 	} else {
 		writer.WriteNull()
 	}
@@ -461,7 +453,7 @@ func zrangeCommand(writer *RESPWriter, args []RESP) {
 	}
 	start = min(start, stop)
 
-	withScores := len(args) == 4 && equalFoldBytes(args[3], WITH_SCORES)
+	withScores := len(args) == 4 && equalFold(args[3].ToStringUnsafe(), WITH_SCORES)
 	if withScores {
 		writer.WriteArrayHead((stop - start) * 2)
 		zset.Range(start, stop, func(key string, score float64) {
@@ -478,7 +470,7 @@ func zrangeCommand(writer *RESPWriter, args []RESP) {
 }
 
 func zpopminCommand(writer *RESPWriter, args []RESP) {
-	key := args[0].ToString()
+	key := args[0].ToStringUnsafe()
 	count := 1
 	var err error
 	if len(args) > 1 {

resp.go

@@ -1,8 +1,8 @@
 package main
 
 import (
+	"bytes"
 	"io"
-	"slices"
 	"strconv"
 	"unsafe"
 )
@@ -28,20 +28,23 @@ func NewReader(input []byte) *RESPReader {
 	return &RESPReader{b: input}
 }
 
-// cutByCRLF splits the buffer by the first occurrence of CRLF.
-func cutByCRLF(buf []byte) (before, after []byte, found bool) {
-	n := len(buf)
-	if n <= 2 {
-		return
-	}
-	for i, b := range buf[:n-1] {
+// parseInt parse first integer from buf.
+// input "3\r\nHELLO" -> (3, "HELLO", nil).
+func parseInt(buf []byte) (n int, after []byte, err error) {
+	for i, b := range buf {
+		if b >= '0' && b <= '9' {
+			n = n*10 + int(b-'0')
+			continue
+		}
 		if b == '\r' {
-			if buf[i+1] == '\n' {
-				return buf[:i], buf[i+2:], true
+			if len(buf) > i+1 && buf[i+1] == '\n' {
+				return n, buf[i+2:], nil
 			}
+			break
 		}
+		return 0, nil, errParseInteger
 	}
-	return
+	return 0, nil, errCRLFNotFound
 }
 
 // ReadNextCommand reads the next RESP command from the RESPReader.
@@ -55,45 +58,37 @@ func (r *RESPReader) ReadNextCommand(argsBuf []RESP) (args []RESP, err error) {
 	switch r.b[0] {
 	case ARRAY:
 		// command_bulk format
-		before, after, ok := cutByCRLF(r.b[1:])
-		if !ok {
-			return nil, errCRLFNotFound
-		}
-		count, err := strconv.Atoi(b2s(before))
+		num, after, err := parseInt(r.b[1:])
 		if err != nil {
 			return nil, err
 		}
 		r.b = after
 
 		// read bulk strings for range
-		for i := 0; i < count; i++ {
+		for i := 0; i < num; i++ {
 			if len(r.b) == 0 || r.b[0] != BULK {
 				return nil, errInvalidArguments
 			}
 
-			// read CRLF
-			before, after, ok := cutByCRLF(r.b[1:])
-			if !ok {
-				return nil, errCRLFNotFound
-			}
-			count, err := strconv.Atoi(b2s(before))
+			num, after, err := parseInt(r.b[1:])
 			if err != nil {
 				return nil, err
 			}
-			r.b = after
 
 			// bound check
-			if count < 0 || count+2 > len(r.b) {
+			if num < 0 || num+2 > len(after) {
 				return nil, errInvalidArguments
 			}
 
-			args = append(args, r.b[:count])
-			r.b = r.b[count+2:]
+			args = append(args, after[:num])
+
+			// skip CRLF
+			r.b = after[num+2:]
 		}
 
 	default:
 		// command_inline format
-		before, after, ok := cutByCRLF(r.b)
+		before, after, ok := bytes.Cut(r.b, CRLF)
 		if !ok {
 			return nil, errInvalidArguments
 		}
@@ -179,8 +174,6 @@ func (r RESP) ToInt() (int, error) { return strconv.Atoi(b2s(r)) }
 
 func (r RESP) ToFloat() (float64, error) { return strconv.ParseFloat(b2s(r), 64) }
 
-func (r RESP) Clone() []byte { return slices.Clone(r) }
+func (r RESP) Clone() []byte { return bytes.Clone(r) }
 
-func b2s(b []byte) string {
-	return *(*string)(unsafe.Pointer(&b))
-}
+func b2s(b []byte) string { return *(*string)(unsafe.Pointer(&b)) }

resp_test.go

@@ -61,26 +61,26 @@ func TestReader(t *testing.T) {
 		}
 	})
 
-	t.Run("cutByCRLF", func(t *testing.T) {
-		before, after, ok := cutByCRLF([]byte("123\r\n456"))
-		assert.Equal(string(before), "123")
-		assert.Equal(string(after), "456")
-		assert.True(ok)
-
-		before, after, ok = cutByCRLF([]byte("1234\r\n5678"))
-		assert.Equal(string(before), "1234")
-		assert.Equal(string(after), "5678")
-		assert.True(ok)
-
-		// error cases
-		_, _, ok = cutByCRLF([]byte("A"))
-		assert.False(ok)
-
-		_, _, ok = cutByCRLF([]byte("ABC"))
-		assert.False(ok)
-
-		_, _, ok = cutByCRLF([]byte("1234\r"))
-		assert.False(ok)
+	t.Run("parseInt", func(t *testing.T) {
+		n, after, err := parseInt([]byte("3\r\nHELLO"))
+		assert.Equal(n, 3)
+		assert.Equal(after, []byte("HELLO"))
+		assert.Nil(err)
+
+		n, after, err = parseInt([]byte("003\r\nHELLO"))
+		assert.Equal(n, 3)
+		assert.Equal(after, []byte("HELLO"))
+		assert.Nil(err)
+
+		// errors
+		_, _, err = parseInt([]byte("ABC\r\nHELLO"))
+		assert.ErrorIs(err, errParseInteger)
+
+		_, _, err = parseInt([]byte("1234567\r"))
+		assert.ErrorIs(err, errCRLFNotFound)
+
+		_, _, err = parseInt([]byte("1234567"))
+		assert.ErrorIs(err, errCRLFNotFound)
 	})
 
 	t.Run("command-bulk", func(t *testing.T) {
@@ -93,11 +93,11 @@ func TestReader(t *testing.T) {
 		// error
 		args, err = NewReader([]byte("*A\r\n$3\r\nGET\r\n$3\r\nfoo\r\n")).ReadNextCommand(nil)
 		assert.Equal(len(args), 0)
-		assert.NotNil(err)
+		assert.ErrorIs(err, errParseInteger)
 
 		args, err = NewReader([]byte("*3\r\n$A\r\nGET\r\n$3\r\nfoo\r\n")).ReadNextCommand(nil)
 		assert.Equal(len(args), 0)
-		assert.NotNil(err)
+		assert.ErrorIs(err, errParseInteger)
 
 		args, err = NewReader([]byte("*3\r\n+PING")).ReadNextCommand(nil)
 		assert.Equal(len(args), 0)