libbpf: remove likely/unlikely in xsk.h

This patch removes the use of likely and unlikely in xsk.h since they create a dependency on Linux headers as reported by several users. There have also been reports that the use of these decreases performance as the compiler puts the code on two different cache lines instead of on a single one. All in all, I think we are better off without them. Fixes: 1cad078 ("libbpf: add support for using AF_XDP sockets") Signed-off-by: Magnus Karlsson <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]>
Sonicadvance1 · Apr 17, 2019 · a06d729 · a06d729
1 parent d5e63fd
commit a06d729
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/tools/lib/bpf/xsk.h b/tools/lib/bpf/xsk.h
@@ -109,7 +109,7 @@ static inline __u32 xsk_cons_nb_avail(struct xsk_ring_cons *r, __u32 nb)
 static inline size_t xsk_ring_prod__reserve(struct xsk_ring_prod *prod,
 					    size_t nb, __u32 *idx)
 {
-	if (unlikely(xsk_prod_nb_free(prod, nb) < nb))
+	if (xsk_prod_nb_free(prod, nb) < nb)
 		return 0;
 
 	*idx = prod->cached_prod;
@@ -133,7 +133,7 @@ static inline size_t xsk_ring_cons__peek(struct xsk_ring_cons *cons,
 {
 	size_t entries = xsk_cons_nb_avail(cons, nb);
 
-	if (likely(entries > 0)) {
+	if (entries > 0) {
 		/* Make sure we do not speculatively read the data before
 		 * we have received the packet buffers from the ring.
 		 */