diff --git a/README.md b/README.md
index 7132dc30..6a717fcc 100644
--- a/README.md
+++ b/README.md
@@ -363,13 +363,10 @@ import (
     "fmt"
     "testing"
 
-    "github.com/xhd2015/xgo/runtime/trace"
+    _ "github.com/xhd2015/xgo/runtime/trace"
 )
 
 func TestTrace(t *testing.T) {
-    // begin trace
-    finish := trace.Begin()
-    defer finish()
     A()
     B()
     C()
@@ -385,7 +382,8 @@ Run with `xgo`:
 ```sh
 # run the test
 # this will write the trace into TestTrace.json
-xgo test ./
+# --strace represents stack trace
+xgo test --strace ./
 
 # view the trace
 xgo tool trace TestTrace.json
@@ -407,6 +405,20 @@ By default, Trace will write traces to a temp directory under current working di
 - `XGO_TRACE_OUTPUT=<dir>`: traces will be written to `<dir>`,
 - `XGO_TRACE_OUTPUT=off`: turn off trace.
 
+Besides the `--strace` flag, xgo allows you to define which span should be collected, using `trace.Begin()`:
+```go
+import "github.com/xhd2015/xgo/runtime/trace"
+
+func TestTrace(t *testing.T) {
+    A()
+    finish := trace.Begin()
+    defer finish()
+    B()
+    C()
+}
+```
+The trace will only include `B()` and `C()`
+
 # Concurrent safety
 I know you guys from other monkey patching library suffer from the unsafety implied by these frameworks.
 
diff --git a/README_zh_cn.md b/README_zh_cn.md
index 50307ac2..1ebc958f 100644
--- a/README_zh_cn.md
+++ b/README_zh_cn.md
@@ -354,13 +354,10 @@ import (
     "fmt"
     "testing"
 
-    "github.com/xhd2015/xgo/runtime/trace"
+    _ "github.com/xhd2015/xgo/runtime/trace"
 )
 
 func TestTrace(t *testing.T) {
-    // begin trace
-    finish := trace.Begin()
-    defer finish()
     A()
     B()
     C()
@@ -397,6 +394,20 @@ xgo tool trace TestTrace.json
 - `XGO_TRACE_OUTPUT=<dir>`: 堆栈记录被写入到`<dir>`目录下,
 - `XGO_TRACE_OUTPUT=off`: 关闭堆栈记录收集。
 
+除了使用`--strace`之外, xgo还允许你通过`trace.Begin()`的方式手动控制追踪范围:
+```go
+import "github.com/xhd2015/xgo/runtime/trace"
+
+func TestTrace(t *testing.T) {
+    A()
+    finish := trace.Begin()
+    defer finish()
+    B()
+    C()
+}
+```
+结果中只会包含`B()`和`C()`.
+
 # 并发安全
 我知道大部分人认为Monkey Patching不是并发安全的，但那是现有的库的实现方式决定的。
 
diff --git a/cmd/xgo/version.go b/cmd/xgo/version.go
index d8d9e221..b809324c 100644
--- a/cmd/xgo/version.go
+++ b/cmd/xgo/version.go
@@ -3,8 +3,8 @@ package main
 import "fmt"
 
 const VERSION = "1.0.25"
-const REVISION = "6eeff524a454a6032a2294b47d1dc1c892b5545f+1"
-const NUMBER = 186
+const REVISION = "ae8695c56e8c7f1976d409c7fba953041983c299+1"
+const NUMBER = 187
 
 func getRevision() string {
 	revSuffix := ""
diff --git a/runtime/core/version.go b/runtime/core/version.go
index 98a35b5a..61342fab 100644
--- a/runtime/core/version.go
+++ b/runtime/core/version.go
@@ -7,8 +7,8 @@ import (
 )
 
 const VERSION = "1.0.25"
-const REVISION = "6eeff524a454a6032a2294b47d1dc1c892b5545f+1"
-const NUMBER = 186
+const REVISION = "ae8695c56e8c7f1976d409c7fba953041983c299+1"
+const NUMBER = 187
 
 // these fields will be filled by compiler
 const XGO_VERSION = ""
diff --git a/runtime/trap/interceptor.go b/runtime/trap/interceptor.go
index 4342d45e..1da4a75a 100644
--- a/runtime/trap/interceptor.go
+++ b/runtime/trap/interceptor.go
@@ -126,6 +126,24 @@ type interceptorManager struct {
 	funcMapping map[*core.FuncInfo][]*Interceptor // nested mapping
 }
 
+func (c *interceptorManager) hasAny() bool {
+	if c == nil {
+		return false
+	}
+	if len(c.head) > 0 {
+		return true
+	}
+	if len(c.tail) > 0 {
+		return true
+	}
+	for _, m := range c.funcMapping {
+		if len(m) > 0 {
+			return true
+		}
+	}
+	return false
+}
+
 func (c *interceptorManager) copy() *interceptorManager {
 	if c == nil {
 		return nil
diff --git a/runtime/trap/trap.go b/runtime/trap/trap.go
index 85b973e6..b9a7b847 100644
--- a/runtime/trap/trap.go
+++ b/runtime/trap/trap.go
@@ -38,7 +38,7 @@ func init() {
 			return
 		}
 		local := getLocalInterceptorList()
-		if local == nil || (len(local.head) == 0 && len(local.tail) == 0) {
+		if !local.hasAny() {
 			return
 		}
 		// inherit interceptors of last group