diff --git a/example/main.go b/example/main.go
index dabdd6c..7039982 100755
--- a/example/main.go
+++ b/example/main.go
@@ -120,6 +120,7 @@ func main() {
 		// SetLevelWriter(glg.WARN, customWriter).
 		// SetLevelWriter(glg.ERR, customWriter).
 		// EnableJSON().
+		SetLineTraceMode(glg.TraceLineNone).
 		AddLevelWriter(glg.INFO, infolog). // add info log file destination
 		AddLevelWriter(glg.ERR, errlog).   // add error log file destination
 		AddLevelWriter(glg.WARN, rotate)   // add error log file destination
@@ -173,23 +174,30 @@ func main() {
 	glg.Info("kpango's glg support line trace logging")
 	glg.Error("error log shows short line trace by default")
 	glg.Info("error log shows none trace by default")
-	glg.Get().SetTraceLineFlag(glg.LTraceLineShort)
-	glg.Error("after configure LTraceLineShort, error log shows short line trace")
-	glg.Info("after configure LTraceLineShort, info log shows short line trace")
+	glg.Get().SetLineTraceMode(glg.TraceLineShort)
+	glg.Error("after configure TraceLineShort, error log shows short line trace")
+	glg.Info("after configure TraceLineShort, info log shows short line trace")
 	glg.Get().DisableTimestamp()
-	glg.Error("after configure LTraceLineShort and DisableTimestamp, error log shows short line trace without timestamp")
-	glg.Info("after configure LTraceLineShort and DisableTimestamp, info log shows short line trace without timestamp")
+	glg.Error("after configure TraceLineShort and DisableTimestamp, error log shows short line trace without timestamp")
+	glg.Info("after configure TraceLineShort and DisableTimestamp, info log shows short line trace without timestamp")
 	glg.Get().EnableTimestamp()
-
-	glg.Get().SetTraceLineFlag(glg.LTraceLineLong)
-	glg.Error("after configure LTraceLineLong, error log shows long line trace")
-	glg.Info("after configure LTraceLineLong, info log shows long line trace")
+	glg.Get().SetLineTraceMode(glg.TraceLineLong)
+	glg.Error("after configure TraceLineLong, error log shows long line trace")
+	glg.Info("after configure TraceLineLong, info log shows long line trace")
 	glg.Get().DisableTimestamp()
-	glg.Error("after configure LTraceLineLong and DisableTimestamp, error log shows long line trace without timestamp")
-	glg.Info("after configure LTraceLineLong and DisableTimestamp, info log shows long line trace without timestamp")
+	glg.Error("after configure TraceLineLong and DisableTimestamp, error log shows long line trace without timestamp")
+	glg.Info("after configure TraceLineLong and DisableTimestamp, info log shows long line trace without timestamp")
 	glg.Get().EnableTimestamp()
-	glg.Get().SetTraceLineFlag(glg.LTraceLineNone)
-	glg.Error("after configure LTraceLineNone, error log shows long line trace")
+	glg.Get().SetLineTraceMode(glg.TraceLineNone)
+	glg.Error("after configure TraceLineNone, error log without line trace")
+	glg.Info("after configure TraceLineNone, info log without line trace")
+	glg.Get().SetLevelLineTraceMode(glg.INFO, glg.TraceLineLong)
+	glg.Info("after configure Level trace INFO=TraceLineLong, only info log shows long line trace")
+	glg.Error("after configure Level trace INFO=TraceLineLong, error log without long line trace")
+	glg.Get().SetLevelLineTraceMode(glg.ERR, glg.TraceLineShort)
+	glg.Info("after configure Level trace ERR=TraceLineShort, info log still shows long line trace")
+	glg.Error("after configure Level trace ERR=TraceLineShort, error log now shows short line trace")
+	glg.Get().SetLineTraceMode(glg.TraceLineNone)
 
 	glg.Info("kpango's glg support json logging")
 	glg.Get().EnableJSON()
diff --git a/glg.go b/glg.go
index ed0a2f9..5202131 100755
--- a/glg.go
+++ b/glg.go
@@ -69,6 +69,8 @@ type LEVEL uint8
 
 type wMode uint8
 
+type traceMode int64
+
 type logger struct {
 	tag              string
 	rawtag           []byte
@@ -76,7 +78,7 @@ type logger struct {
 	std              io.Writer
 	color            func(string) string
 	isColor          bool
-	flag             int
+	traceMode        traceMode
 	mode             MODE
 	prevMode         MODE
 	writeMode        wMode
@@ -145,10 +147,9 @@ const (
 	sep   = "]:" + tab
 	sepl  = len(sep)
 
-	// LTraceLine is flags for tracing log line
-	LTraceLineNone = 1 << iota
-	LTraceLineShort
-	LTraceLineLong
+	TraceLineNone traceMode = 1 << iota
+	TraceLineShort
+	TraceLineLong
 )
 
 var (
@@ -227,75 +228,75 @@ func New() *Glg {
 	for lev, log := range map[LEVEL]*logger{
 		// standard out
 		DEBG: {
-			std:     os.Stdout,
-			color:   Purple,
-			isColor: true,
-			mode:    STD,
-			flag:    LTraceLineNone,
+			std:       os.Stdout,
+			color:     Purple,
+			isColor:   true,
+			mode:      STD,
+			traceMode: TraceLineNone,
 		},
 		TRACE: {
-			std:     os.Stdout,
-			color:   Yellow,
-			isColor: true,
-			mode:    STD,
-			flag:    LTraceLineNone,
+			std:       os.Stdout,
+			color:     Yellow,
+			isColor:   true,
+			mode:      STD,
+			traceMode: TraceLineNone,
 		},
 		PRINT: {
-			std:     os.Stdout,
-			color:   Colorless,
-			isColor: true,
-			mode:    STD,
-			flag:    LTraceLineNone,
+			std:       os.Stdout,
+			color:     Colorless,
+			isColor:   true,
+			mode:      STD,
+			traceMode: TraceLineNone,
 		},
 		LOG: {
-			std:     os.Stdout,
-			color:   Colorless,
-			isColor: true,
-			mode:    STD,
-			flag:    LTraceLineNone,
+			std:       os.Stdout,
+			color:     Colorless,
+			isColor:   true,
+			mode:      STD,
+			traceMode: TraceLineNone,
 		},
 		INFO: {
-			std:     os.Stdout,
-			color:   Green,
-			isColor: true,
-			mode:    STD,
-			flag:    LTraceLineNone,
+			std:       os.Stdout,
+			color:     Green,
+			isColor:   true,
+			mode:      STD,
+			traceMode: TraceLineNone,
 		},
 		OK: {
-			std:     os.Stdout,
-			color:   Cyan,
-			isColor: true,
-			mode:    STD,
-			flag:    LTraceLineNone,
+			std:       os.Stdout,
+			color:     Cyan,
+			isColor:   true,
+			mode:      STD,
+			traceMode: TraceLineNone,
 		},
 		WARN: {
-			std:     os.Stdout,
-			color:   Orange,
-			isColor: true,
-			mode:    STD,
-			flag:    LTraceLineNone,
+			std:       os.Stdout,
+			color:     Orange,
+			isColor:   true,
+			mode:      STD,
+			traceMode: TraceLineNone,
 		},
 		// error out
 		ERR: {
-			std:     os.Stderr,
-			color:   Red,
-			isColor: true,
-			mode:    STD,
-			flag:    LTraceLineShort,
+			std:       os.Stderr,
+			color:     Red,
+			isColor:   true,
+			mode:      STD,
+			traceMode: TraceLineShort,
 		},
 		FAIL: {
-			std:     os.Stderr,
-			color:   Red,
-			isColor: true,
-			mode:    STD,
-			flag:    LTraceLineShort,
+			std:       os.Stderr,
+			color:     Red,
+			isColor:   true,
+			mode:      STD,
+			traceMode: TraceLineShort,
 		},
 		FATAL: {
-			std:     os.Stderr,
-			color:   Red,
-			isColor: true,
-			mode:    STD,
-			flag:    LTraceLineLong,
+			std:       os.Stderr,
+			color:     Red,
+			isColor:   true,
+			mode:      STD,
+			traceMode: TraceLineLong,
 		},
 	} {
 		log.tag = lev.String()
@@ -565,21 +566,21 @@ func (g *Glg) DisableLevelTimestamp(lv LEVEL) *Glg {
 	return g
 }
 
-// SetTraceLineFlag configures output line traceFlag
-func (g *Glg) SetTraceLineFlag(flg int) *Glg {
+// SetLineTraceMode configures output line traceFlag
+func (g *Glg) SetLineTraceMode(mode traceMode) *Glg {
 	g.logger.Range(func(lev LEVEL, l *logger) bool {
-		l.flag = flg
+		l.traceMode = mode
 		g.logger.Store(lev, l)
 		return true
 	})
 	return g
 }
 
-// SetLevelTraceLineFlag configures output line traceFlag
-func (g *Glg) SetLevelTraceLineFlag(lv LEVEL, flg int) *Glg {
+// SetLevelLineTraceMode configures output line traceFlag
+func (g *Glg) SetLevelLineTraceMode(lv LEVEL, mode traceMode) *Glg {
 	l, ok := g.logger.Load(lv)
 	if ok {
-		l.flag = flg
+		l.traceMode = mode
 		g.logger.Store(lv, l)
 	}
 	return g
@@ -826,12 +827,12 @@ func (g *Glg) out(level LEVEL, calldepth int, format string, val ...interface{})
 	}
 
 	var fl string
-	if log.flag&(LTraceLineLong|LTraceLineShort) != 0 {
+	if log.traceMode&(TraceLineLong|TraceLineShort) != 0 {
 		_, file, line, ok := runtime.Caller(calldepth)
 		switch {
 		case !ok:
 			fl = "???:0"
-		case log.flag&LTraceLineShort != 0:
+		case log.traceMode&TraceLineShort != 0:
 			for i := len(file) - 1; i > 0; i-- {
 				if file[i] == '/' {
 					file = file[i+1:]
diff --git a/go.mod b/go.mod
index 85558b2..8b3fd67 100644
--- a/go.mod
+++ b/go.mod
@@ -4,7 +4,7 @@ go 1.17
 
 require (
 	github.com/goccy/go-json v0.7.4
-	github.com/kpango/fastime v1.0.16
+	github.com/kpango/fastime v1.0.17
 	github.com/sirupsen/logrus v1.8.1
 	go.uber.org/zap v1.18.1
 )
diff --git a/go.sum b/go.sum
index 9c7b68d..4dee8b8 100644
--- a/go.sum
+++ b/go.sum
@@ -5,8 +5,8 @@ github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/goccy/go-json v0.7.4 h1:B44qRUFwz/vxPKPISQ1KhvzRi9kZ28RAf6YtjriBZ5k=
 github.com/goccy/go-json v0.7.4/go.mod h1:6MelG93GURQebXPDq3khkgXZkazVtN9CRI+MGFi0w8I=
-github.com/kpango/fastime v1.0.16 h1:1prFG/3pTjzcDeCTxt98VB4IvjxcySLs0ldCEhZg0R8=
-github.com/kpango/fastime v1.0.16/go.mod h1:lVqUTcXmQnk1wriyvq5DElbRSRDC0XtqbXQRdz0Eo+g=
+github.com/kpango/fastime v1.0.17 h1:IZOBLEJrr2MIpsY1ihGhpkY+9pEikJWYwPEMu0/VdcY=
+github.com/kpango/fastime v1.0.17/go.mod h1:lVqUTcXmQnk1wriyvq5DElbRSRDC0XtqbXQRdz0Eo+g=
 github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=