Use of rte_smb_wmb() instead of rte_smb_rmb() in sc dequeue
function creates the additional overhead of waiting for
all the STOREs to be completed to local buffer from ring buffer
memory. The sc dequeue function demands only LOAD-STORE barrier
where LOADs from ring buffer memory needs to be
completed before tail pointer update. Changing to rte_smb_rmb()
to enable the required LOAD-STORE barrier.
Fixes: ecc7d10e448e ("ring: guarantee dequeue ordering before tail update")
Signed-off-by: Jerin Jacob <jerin.jacob at caviumnetworks.com>
---
lib/librte_ring/rte_ring.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lib/librte_ring/rte_ring.h b/lib/librte_ring/rte_ring.h
index f928324..0e22e69 100644
--- a/lib/librte_ring/rte_ring.h
+++ b/lib/librte_ring/rte_ring.h
@@ -756,7 +756,7 @@ __rte_ring_sc_do_dequeue(struct rte_ring *r, void
**obj_table,
/* copy in table */
DEQUEUE_PTRS();
- rte_smp_wmb();
+ rte_smp_rmb();
__RING_STAT_ADD(r, deq_success, n);
r->cons.tail = cons_next;
--
2.5.5
