Thread (48 messages) flat view 48 messages, 5 authors, 2017-07-07
STALE3363d

[PATCH 3/5] net/mlx5: use buffer address for LKEY search

From: Yongseok Koh <hidden>
Date: 2017-06-28 23:05:22
Subsystem: networking drivers, the rest · Maintainers: Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds

When searching LKEY, if search key is mempool pointer, the 2nd cacheline
has to be accessed and it even requires to check whether a buffer is
indirect per every search. Instead, using address for search key can reduce
cycles taken. And caching the last hit entry is beneficial as well.

Signed-off-by: Yongseok Koh <redacted>
---
 drivers/net/mlx5/mlx5_mr.c   |  2 ++
 drivers/net/mlx5/mlx5_rxtx.c | 37 ++++++++++++++++++++-----------------
 drivers/net/mlx5/mlx5_rxtx.h |  3 +++
 3 files changed, 25 insertions(+), 17 deletions(-)
diff --git a/drivers/net/mlx5/mlx5_mr.c b/drivers/net/mlx5/mlx5_mr.c
index 0a3638460..f2484cb06 100644
--- a/drivers/net/mlx5/mlx5_mr.c
+++ b/drivers/net/mlx5/mlx5_mr.c
@@ -207,6 +207,8 @@ txq_mp2mr_reg(struct txq *txq, struct rte_mempool *mp, unsigned int idx)
 			 sizeof(txq_ctrl->txq.mp2mr[0])));
 	}
 	/* Store the new entry. */
+	txq_ctrl->txq.mp2mr[idx].start = (uintptr_t)mr->addr;
+	txq_ctrl->txq.mp2mr[idx].end = (uintptr_t)mr->addr + mr->length;
 	txq_ctrl->txq.mp2mr[idx].mp = mp;
 	txq_ctrl->txq.mp2mr[idx].mr = mr;
 	txq_ctrl->txq.mp2mr[idx].lkey = htonl(mr->lkey);
diff --git a/drivers/net/mlx5/mlx5_rxtx.c b/drivers/net/mlx5/mlx5_rxtx.c
index d81d630f7..5cc38ccb7 100644
--- a/drivers/net/mlx5/mlx5_rxtx.c
+++ b/drivers/net/mlx5/mlx5_rxtx.c
@@ -77,7 +77,7 @@ static __rte_always_inline void
 txq_complete(struct txq *txq);
 
 static __rte_always_inline uint32_t
-txq_mp2mr(struct txq *txq, struct rte_mempool *mp);
+txq_mb2mr(struct txq *txq, struct rte_mbuf *mb);
 
 static __rte_always_inline void
 mlx5_tx_dbrec(struct txq *txq, volatile struct mlx5_wqe *wqe);
@@ -355,7 +355,7 @@ txq_mb2mp(struct rte_mbuf *buf)
 }
 
 /**
- * Get Memory Region (MR) <-> Memory Pool (MP) association from txq->mp2mr[].
+ * Get Memory Region (MR) <-> rte_mbuf association from txq->mp2mr[].
  * Add MP to txq->mp2mr[] if it's not registered yet. If mp2mr[] is full,
  * remove an entry first.
  *
@@ -368,27 +368,30 @@ txq_mb2mp(struct rte_mbuf *buf)
  *   mr->lkey on success, (uint32_t)-1 on failure.
  */
 static inline uint32_t
-txq_mp2mr(struct txq *txq, struct rte_mempool *mp)
+txq_mb2mr(struct txq *txq, struct rte_mbuf *mb)
 {
-	unsigned int i;
-	uint32_t lkey = (uint32_t)-1;
+	uint16_t i = txq->mr_cache_idx;
+	uintptr_t addr = rte_pktmbuf_mtod(mb, uintptr_t);
 
+	assert(i < RTE_DIM(txq->mp2mr));
+	if (likely(txq->mp2mr[i].start <= addr && txq->mp2mr[i].end >= addr))
+		return txq->mp2mr[i].lkey;
 	for (i = 0; (i != RTE_DIM(txq->mp2mr)); ++i) {
 		if (unlikely(txq->mp2mr[i].mp == NULL)) {
 			/* Unknown MP, add a new MR for it. */
 			break;
 		}
-		if (txq->mp2mr[i].mp == mp) {
+		if (txq->mp2mr[i].start <= addr &&
+		    txq->mp2mr[i].end >= addr) {
 			assert(txq->mp2mr[i].lkey != (uint32_t)-1);
 			assert(htonl(txq->mp2mr[i].mr->lkey) ==
 			       txq->mp2mr[i].lkey);
-			lkey = txq->mp2mr[i].lkey;
-			break;
+			txq->mr_cache_idx = i;
+			return txq->mp2mr[i].lkey;
 		}
 	}
-	if (unlikely(lkey == (uint32_t)-1))
-		lkey = txq_mp2mr_reg(txq, mp, i);
-	return lkey;
+	txq->mr_cache_idx = 0;
+	return txq_mp2mr_reg(txq, txq_mb2mp(mb), i);
 }
 
 /**
@@ -773,7 +776,7 @@ mlx5_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
 			naddr = htonll(addr);
 			*dseg = (rte_v128u32_t){
 				htonl(length),
-				txq_mp2mr(txq, txq_mb2mp(buf)),
+				txq_mb2mr(txq, buf),
 				naddr,
 				naddr >> 32,
 			};
@@ -812,7 +815,7 @@ mlx5_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
 		naddr = htonll(rte_pktmbuf_mtod(buf, uintptr_t));
 		*dseg = (rte_v128u32_t){
 			htonl(length),
-			txq_mp2mr(txq, txq_mb2mp(buf)),
+			txq_mb2mr(txq, buf),
 			naddr,
 			naddr >> 32,
 		};
@@ -1054,7 +1057,7 @@ mlx5_tx_burst_mpw(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
 			addr = rte_pktmbuf_mtod(buf, uintptr_t);
 			*dseg = (struct mlx5_wqe_data_seg){
 				.byte_count = htonl(DATA_LEN(buf)),
-				.lkey = txq_mp2mr(txq, txq_mb2mp(buf)),
+				.lkey = txq_mb2mr(txq, buf),
 				.addr = htonll(addr),
 			};
 #if defined(MLX5_PMD_SOFT_COUNTERS) || !defined(NDEBUG)
@@ -1300,7 +1303,7 @@ mlx5_tx_burst_mpw_inline(void *dpdk_txq, struct rte_mbuf **pkts,
 				addr = rte_pktmbuf_mtod(buf, uintptr_t);
 				*dseg = (struct mlx5_wqe_data_seg){
 					.byte_count = htonl(DATA_LEN(buf)),
-					.lkey = txq_mp2mr(txq, txq_mb2mp(buf)),
+					.lkey = txq_mb2mr(txq, buf),
 					.addr = htonll(addr),
 				};
 #if defined(MLX5_PMD_SOFT_COUNTERS) || !defined(NDEBUG)
@@ -1607,7 +1610,7 @@ mlx5_tx_burst_empw(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
 				addr = rte_pktmbuf_mtod(buf, uintptr_t);
 				*dseg = (struct mlx5_wqe_data_seg){
 					.byte_count = htonl(DATA_LEN(buf)),
-					.lkey = txq_mp2mr(txq, txq_mb2mp(buf)),
+					.lkey = txq_mb2mr(txq, buf),
 					.addr = htonll(addr),
 				};
 #if defined(MLX5_PMD_SOFT_COUNTERS) || !defined(NDEBUG)
@@ -1690,7 +1693,7 @@ mlx5_tx_burst_empw(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
 			naddr = htonll(addr);
 			*dseg = (rte_v128u32_t) {
 				htonl(length),
-				txq_mp2mr(txq, txq_mb2mp(buf)),
+				txq_mb2mr(txq, buf),
 				naddr,
 				naddr >> 32,
 			};
diff --git a/drivers/net/mlx5/mlx5_rxtx.h b/drivers/net/mlx5/mlx5_rxtx.h
index f9b738b4e..a86f41abc 100644
--- a/drivers/net/mlx5/mlx5_rxtx.h
+++ b/drivers/net/mlx5/mlx5_rxtx.h
@@ -267,10 +267,13 @@ struct txq {
 	volatile uint32_t *cq_db; /* Completion queue doorbell. */
 	volatile void *bf_reg; /* Blueflame register. */
 	struct {
+		uintptr_t start; /* Start address of MR */
+		uintptr_t end;   /* End address of MR */
 		const struct rte_mempool *mp; /* Cached Memory Pool. */
 		struct ibv_mr *mr; /* Memory Region (for mp). */
 		uint32_t lkey; /* htonl(mr->lkey) */
 	} mp2mr[MLX5_PMD_TX_MP_CACHE]; /* MP to MR translation table. */
+	uint16_t mr_cache_idx; /* Index of last hit entry. */
 	struct rte_mbuf *(*elts)[]; /* TX elements. */
 	struct mlx5_txq_stats stats; /* TX queue counters. */
 } __rte_cache_aligned;
-- 
2.11.0
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