X-Git-Url: http://git.droids-corp.org/?a=blobdiff_plain;ds=sidebyside;f=drivers%2Fnet%2Fenetc%2Fenetc_rxtx.c;h=412322523d14284aa949079b79c5d83265b81c40;hb=64767daf3c9eaa4d2b2b00017137ac0566df1c55;hp=8b85c5371951267d29b9c2016d27009f3fa9ce81;hpb=17d13fe659eb6abf4f565a7bfcc4387ba9964bce;p=dpdk.git

diff --git a/drivers/net/enetc/enetc_rxtx.c b/drivers/net/enetc/enetc_rxtx.c
index 8b85c53719..412322523d 100644
--- a/drivers/net/enetc/enetc_rxtx.c
+++ b/drivers/net/enetc/enetc_rxtx.c
@@ -14,14 +14,17 @@
 #include "enetc.h"
 #include "enetc_logs.h"
 
+#define ENETC_CACHE_LINE_RXBDS	(RTE_CACHE_LINE_SIZE / \
+				 sizeof(union enetc_rx_bd))
 #define ENETC_RXBD_BUNDLE 16 /* Number of buffers to allocate at once */
 
 static int
 enetc_clean_tx_ring(struct enetc_bdr *tx_ring)
 {
 	int tx_frm_cnt = 0;
-	struct enetc_swbd *tx_swbd;
-	int i, hwci;
+	struct enetc_swbd *tx_swbd, *tx_swbd_base;
+	int i, hwci, bd_count;
+	struct rte_mbuf *m[ENETC_RXBD_BUNDLE];
 
 	/* we don't need barriers here, we just want a relatively current value
 	 * from HW.
@@ -29,8 +32,10 @@ enetc_clean_tx_ring(struct enetc_bdr *tx_ring)
 	hwci = (int)(rte_read32_relaxed(tx_ring->tcisr) &
 		     ENETC_TBCISR_IDX_MASK);
 
+	tx_swbd_base = tx_ring->q_swbd;
+	bd_count = tx_ring->bd_count;
 	i = tx_ring->next_to_clean;
-	tx_swbd = &tx_ring->q_swbd[i];
+	tx_swbd = &tx_swbd_base[i];
 
 	/* we're only reading the CI index once here, which means HW may update
 	 * it while we're doing clean-up.  We could read the register in a loop
@@ -42,20 +47,33 @@ enetc_clean_tx_ring(struct enetc_bdr *tx_ring)
 	 * meantime.
 	 */
 	while (i != hwci) {
-		rte_pktmbuf_free(tx_swbd->buffer_addr);
+		/* It seems calling rte_pktmbuf_free is wasting a lot of cycles,
+		 * make a list and call _free when it's done.
+		 */
+		if (tx_frm_cnt == ENETC_RXBD_BUNDLE) {
+			rte_pktmbuf_free_bulk(m, tx_frm_cnt);
+			tx_frm_cnt = 0;
+		}
+
+		m[tx_frm_cnt] = tx_swbd->buffer_addr;
 		tx_swbd->buffer_addr = NULL;
-		tx_swbd++;
+
 		i++;
-		if (unlikely(i == tx_ring->bd_count)) {
+		tx_swbd++;
+		if (unlikely(i == bd_count)) {
 			i = 0;
-			tx_swbd = &tx_ring->q_swbd[0];
+			tx_swbd = tx_swbd_base;
 		}
 
 		tx_frm_cnt++;
 	}
 
+	if (tx_frm_cnt)
+		rte_pktmbuf_free_bulk(m, tx_frm_cnt);
+
 	tx_ring->next_to_clean = i;
-	return tx_frm_cnt++;
+
+	return 0;
 }
 
 uint16_t
@@ -234,7 +252,7 @@ static inline void enetc_slow_parsing(struct rte_mbuf *m,
 }
 
 
-static inline void __attribute__((hot))
+static inline void __rte_hot
 enetc_dev_rx_parse(struct rte_mbuf *m, uint16_t parse_results)
 {
 	ENETC_PMD_DP_DEBUG("parse summary = 0x%x   ", parse_results);
@@ -305,18 +323,37 @@ enetc_clean_rx_ring(struct enetc_bdr *rx_ring,
 		    int work_limit)
 {
 	int rx_frm_cnt = 0;
-	int cleaned_cnt, i;
+	int cleaned_cnt, i, bd_count;
 	struct enetc_swbd *rx_swbd;
+	union enetc_rx_bd *rxbd;
 
-	cleaned_cnt = enetc_bd_unused(rx_ring);
 	/* next descriptor to process */
 	i = rx_ring->next_to_clean;
+	/* next descriptor to process */
+	rxbd = ENETC_RXBD(*rx_ring, i);
+	rte_prefetch0(rxbd);
+	bd_count = rx_ring->bd_count;
+	/* LS1028A does not have platform cache so any software access following
+	 * a hardware write will go directly to DDR.  Latency of such a read is
+	 * in excess of 100 core cycles, so try to prefetch more in advance to
+	 * mitigate this.
+	 * How much is worth prefetching really depends on traffic conditions.
+	 * With congested Rx this could go up to 4 cache lines or so.  But if
+	 * software keeps up with hardware and follows behind Rx PI by a cache
+	 * line or less then it's harmful in terms of performance to cache more.
+	 * We would only prefetch BDs that have yet to be written by ENETC,
+	 * which will have to be evicted again anyway.
+	 */
+	rte_prefetch0(ENETC_RXBD(*rx_ring,
+				 (i + ENETC_CACHE_LINE_RXBDS) % bd_count));
+	rte_prefetch0(ENETC_RXBD(*rx_ring,
+				 (i + ENETC_CACHE_LINE_RXBDS * 2) % bd_count));
+
+	cleaned_cnt = enetc_bd_unused(rx_ring);
 	rx_swbd = &rx_ring->q_swbd[i];
 	while (likely(rx_frm_cnt < work_limit)) {
-		union enetc_rx_bd *rxbd;
 		uint32_t bd_status;
 
-		rxbd = ENETC_RXBD(*rx_ring, i);
 		bd_status = rte_le_to_cpu_32(rxbd->r.lstatus);
 		if (!bd_status)
 			break;
@@ -337,11 +374,18 @@ enetc_clean_rx_ring(struct enetc_bdr *rx_ring,
 			i = 0;
 			rx_swbd = &rx_ring->q_swbd[i];
 		}
+		rxbd = ENETC_RXBD(*rx_ring, i);
+		rte_prefetch0(ENETC_RXBD(*rx_ring,
+					 (i + ENETC_CACHE_LINE_RXBDS) %
+					  bd_count));
+		rte_prefetch0(ENETC_RXBD(*rx_ring,
+					 (i + ENETC_CACHE_LINE_RXBDS * 2) %
+					 bd_count));
 
-		rx_ring->next_to_clean = i;
 		rx_frm_cnt++;
 	}
 
+	rx_ring->next_to_clean = i;
 	enetc_refill_rx_ring(rx_ring, cleaned_cnt);
 
 	return rx_frm_cnt;