[dpdk-dev] [PATCH v2 2/2] net/bnxt: performance fix for Arm

[Kalesh A P]

From: Rahul Gupta <rahul.gupta at broadcom.com>

Eliminate unnecessary rte_smp_wmb() before writing to request/completion
doorbells. Use rte_cio_wmb() memory barrier instead of rte_io_wmb() before
writing to tx/rx request queue doorbells and use rte_compiler_barrier()
before writing to tx/rx completion queue doorbells.

Fixes: 4af9d0c72941 ("net/bnxt: cleanup NQ doorbell")
Fixes: f8168ca0e690 ("net/bnxt: support thor controller")
Cc: stable at dpdk.org

Signed-off-by: Rahul Gupta <rahul.gupta at broadcom.com>
Signed-off-by: Kalesh AP <kalesh-anakkur.purayil at broadcom.com>
Reviewed-by: Ajit Kumar Khaparde <ajit.khaparde at broadcom.com>
Reviewed-by: Lance Richardson <lance.richardson at broadcom.com>
---
 drivers/net/bnxt/bnxt_cpr.h  |  6 +++---
 drivers/net/bnxt/bnxt_ring.h | 24 +++++++++++++-----------
 2 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/drivers/net/bnxt/bnxt_cpr.h b/drivers/net/bnxt/bnxt_cpr.h
index c288078..cccd6cd 100644
--- a/drivers/net/bnxt/bnxt_cpr.h
+++ b/drivers/net/bnxt/bnxt_cpr.h
@@ -64,9 +64,9 @@ struct bnxt_db_info;
 				(cons));				\
 } while (0)
 #define B_CP_DIS_DB(cpr, raw_cons)					\
-	rte_write32((DB_CP_FLAGS |					\
-		    RING_CMP(((cpr)->cp_ring_struct), raw_cons)),	\
-		    ((cpr)->cp_db.doorbell))
+	rte_write32_relaxed((DB_CP_FLAGS |				\
+			    RING_CMP(((cpr)->cp_ring_struct), raw_cons)), \
+			    ((cpr)->cp_db.doorbell))
 
 #define B_CP_DB(cpr, raw_cons, ring_mask)				\
 	rte_write32((DB_CP_FLAGS |					\
diff --git a/drivers/net/bnxt/bnxt_ring.h b/drivers/net/bnxt/bnxt_ring.h
index 48a39d7..9913aed 100644
--- a/drivers/net/bnxt/bnxt_ring.h
+++ b/drivers/net/bnxt/bnxt_ring.h
@@ -82,10 +82,12 @@ void bnxt_free_rxtx_nq_ring(struct bnxt *bp);
 
 static inline void bnxt_db_write(struct bnxt_db_info *db, uint32_t idx)
 {
+	rte_cio_wmb();
+
 	if (db->db_64)
 		rte_write64_relaxed(db->db_key64 | idx, db->doorbell);
 	else
-		rte_write32(db->db_key32 | idx, db->doorbell);
+		rte_write32_relaxed(db->db_key32 | idx, db->doorbell);
 }
 
 /* Ring an NQ doorbell and disable interrupts for the ring. */
@@ -94,10 +96,10 @@ static inline void bnxt_db_nq(struct bnxt_cp_ring_info *cpr)
 	if (unlikely(!cpr->cp_db.db_64))
 		return;
 
-	rte_smp_wmb();
-	rte_write64(cpr->cp_db.db_key64 | DBR_TYPE_NQ |
-		    RING_CMP(cpr->cp_ring_struct, cpr->cp_raw_cons),
-		    cpr->cp_db.doorbell);
+	rte_cio_wmb();
+	rte_write64_relaxed(cpr->cp_db.db_key64 | DBR_TYPE_NQ |
+			    RING_CMP(cpr->cp_ring_struct, cpr->cp_raw_cons),
+			    cpr->cp_db.doorbell);
 }
 
 /* Ring an NQ doorbell and enable interrupts for the ring. */
@@ -106,10 +108,10 @@ static inline void bnxt_db_nq_arm(struct bnxt_cp_ring_info *cpr)
 	if (unlikely(!cpr->cp_db.db_64))
 		return;
 
-	rte_smp_wmb();
-	rte_write64(cpr->cp_db.db_key64 | DBR_TYPE_NQ_ARM |
-		    RING_CMP(cpr->cp_ring_struct, cpr->cp_raw_cons),
-		    cpr->cp_db.doorbell);
+	rte_cio_wmb();
+	rte_write64_relaxed(cpr->cp_db.db_key64 | DBR_TYPE_NQ_ARM |
+			    RING_CMP(cpr->cp_ring_struct, cpr->cp_raw_cons),
+			    cpr->cp_db.doorbell);
 }
 
 static inline void bnxt_db_cq(struct bnxt_cp_ring_info *cpr)
@@ -117,9 +119,9 @@ static inline void bnxt_db_cq(struct bnxt_cp_ring_info *cpr)
 	struct bnxt_db_info *db = &cpr->cp_db;
 	uint32_t idx = RING_CMP(cpr->cp_ring_struct, cpr->cp_raw_cons);
 
-	rte_smp_wmb();
+	rte_compiler_barrier();
 	if (db->db_64)
-		rte_write64(db->db_key64 | idx, db->doorbell);
+		rte_write64_relaxed(db->db_key64 | idx, db->doorbell);
 	else
 		B_CP_DIS_DB(cpr, cpr->cp_raw_cons);
 }
-- 
2.10.1