likely/unlikely support

Branch mispredicution could cost performance loss. Add vr_likely and vr_unlikely support to assist compiler. Change-Id: I5a0a2210ea0d1f092f2543b52d0a145f38a33335 Partial-Bug: #1769570 Signed-off-by: Yipeng Wang <yipeng1.wang@intel.com>
Juniper · May 3, 2019 · aee12a3 · aee12a3
1 parent 698dc5c
commit aee12a3
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/include/vr_os.h b/include/vr_os.h
@@ -36,6 +36,11 @@
 #define vr_sync_lock_test_and_set_p(a, b)               __sync_lock_test_and_set((a), (b))
 #define vr_sync_synchronize                             __sync_synchronize
 #define vr_ffs_32(a)                                    __builtin_ffs(a)
+#define vr_likely(a)                                    __builtin_expect(!!(a), 1)
+#define vr_unlikely(a)                                  __builtin_expect(!!(a), 0)
+#else
+#define vr_likely(a)                                    (a)
+#define vr_unlikely(a)                                  (a)
 #endif
 
 #if defined(__linux__)