diff --git a/lang/mcache/bsr_amd64.go b/lang/mcache/bsr_amd64.go
deleted file mode 100644
index fe9d7504..00000000
--- a/lang/mcache/bsr_amd64.go
+++ /dev/null
@@ -1,19 +0,0 @@
-// Copyright 2021 ByteDance Inc.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package mcache
-
-func bsr(x int) int
-
-func lzcnt(x int) int
diff --git a/lang/mcache/bsr_amd64.s b/lang/mcache/bsr_amd64.s
deleted file mode 100644
index 8a73f1e8..00000000
--- a/lang/mcache/bsr_amd64.s
+++ /dev/null
@@ -1,27 +0,0 @@
-// Copyright 2021 ByteDance Inc.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#include "textflag.h"
-
-// func lzcnt(x int) int
-TEXT ·lzcnt(SB), NOSPLIT, $0-16
-    LZCNTQ x+0(FP), AX
-    MOVQ AX, ret+8(FP)
-    RET
-
-// func bsr(x int) int
-TEXT ·bsr(SB), NOSPLIT, $0-16
-    BSRQ x+0(FP), AX
-    MOVQ AX, ret+8(FP)
-    RET
diff --git a/lang/mcache/bsr_other.go b/lang/mcache/bsr_other.go
deleted file mode 100644
index 636de30f..00000000
--- a/lang/mcache/bsr_other.go
+++ /dev/null
@@ -1,27 +0,0 @@
-// Copyright 2021 ByteDance Inc.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-//go:build !amd64
-// +build !amd64
-
-package mcache
-
-func bsr(x int) int {
-	r := 0
-	for x != 0 {
-		x = x >> 1
-		r += 1
-	}
-	return r - 1
-}
diff --git a/lang/mcache/utils.go b/lang/mcache/utils.go
index 38d6cb2e..71326f92 100644
--- a/lang/mcache/utils.go
+++ b/lang/mcache/utils.go
@@ -14,6 +14,12 @@
 
 package mcache
 
+import "math/bits"
+
+func bsr(x int) int {
+	return bits.Len(uint(x)) - 1
+}
+
 func isPowerOfTwo(x int) bool {
 	return (x & (-x)) == x
 }
diff --git a/lang/mcache/bsr_test.go b/lang/mcache/utils_test.go
similarity index 82%
rename from lang/mcache/bsr_test.go
rename to lang/mcache/utils_test.go
index 3239231a..50117f0f 100644
--- a/lang/mcache/bsr_test.go
+++ b/lang/mcache/utils_test.go
@@ -26,3 +26,13 @@ func TestBsr(t *testing.T) {
 	assert.Equal(t, bsr((1<<10)-1), 9)
 	assert.Equal(t, bsr((1<<30)+(1<<19)+(1<<16)+(1<<1)), 30)
 }
+
+func BenchmarkBsr(b *testing.B) {
+	num := (1 << 30) + (1 << 19) + (1 << 16) + (1 << 1)
+
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_ = bsr(num + i)
+	}
+}