diff --git a/misc/likely.cpp b/misc/likely.cpp
new file mode 100644
index 0000000..202e11b
--- /dev/null
+++ b/misc/likely.cpp
@@ -0,0 +1,85 @@
+#include <iostream>
+#include <thread>
+#include <chrono>
+#include <sys/time.h>
+#include <limits.h>
+
+#define likely(x) __builtin_expect(!!(x), 1)
+#define unlikely(x) __builtin_expect(!!(x), 0)
+
+using namespace std;
+#define SIZE 500000000
+
+int arr[SIZE];
+
+void func(int *pval)
+{
+    double ret = 0;
+    timeval start, end;
+    gettimeofday(&start, nullptr);
+    while (*pval)
+    {
+        if (((*pval) == 256))
+            ret = ret + 1234;
+        else
+            ret = ret + 5678;
+        pval++;
+    }
+    gettimeofday(&end, nullptr);
+    double usec = (end.tv_sec - start.tv_sec) + (double)(end.tv_usec - start.tv_usec) / 1000000;
+    cout << __func__ << " duration: " << usec << ", ret: " << ret << endl;
+}
+
+void func_likely(int *pval)
+{
+    double ret = 0;
+    timeval start, end;
+    gettimeofday(&start, nullptr);
+    while (*pval)
+    {
+        if (likely((*pval) == 256))
+            ret = ret + 1234;
+        else
+            ret = ret + 5678;
+        pval++;
+    }
+    gettimeofday(&end, nullptr);
+    double usec = (end.tv_sec - start.tv_sec) + (double)(end.tv_usec - start.tv_usec) / 1000000;
+    cout << __func__ << " duration: " << usec << ", ret: " << ret << endl;
+}
+
+void func_unlikely(int *pval)
+{
+    double ret = 0;
+    timeval start, end;
+    gettimeofday(&start, nullptr);
+    while (*pval)
+    {
+        if (unlikely((*pval) == 256))
+            ret = ret + 1234;
+        else
+            ret = ret + 5678;
+        pval++;
+    }
+    gettimeofday(&end, nullptr);
+    double usec = (end.tv_sec - start.tv_sec) + (double)(end.tv_usec - start.tv_usec) / 1000000;
+    cout << __func__ << " duration: " << usec << ", ret: " << ret << endl;
+}
+
+int main()
+{
+    for (int i = 0; i < SIZE; i++)
+    {
+        if (i % 1000 == 0)
+            *(arr + i) = 256;
+        else
+            *(arr + i) = 128;
+    }
+    arr[SIZE - 1] = 0;
+    std::thread t1(func, arr);
+    std::thread t2(func_likely, arr);
+    std::thread t3(func_unlikely, arr);
+    t1.join();
+    t2.join();
+    t3.join();
+}
\ No newline at end of file