[PATCH 1/5] net: mvneta: increase the 64-bit rx/tx stats out of the hot path
From: Willy Tarreau <w@1wt.eu>
Date: 2014-01-12 09:31:59
Subsystem:
marvell mvneta ethernet driver, networking drivers, the rest · Maintainers:
Marcin Wojtas, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Better count packets and bytes in the stack and on 32 bit then accumulate them at the end for once. This saves two memory writes and two memory barriers per packet. The incoming packet rate was increased by 4.7% on the Openblocks AX3 thanks to this. Cc: Thomas Petazzoni <redacted> Cc: Gregory CLEMENT <redacted> Signed-off-by: Willy Tarreau <w@1wt.eu> --- drivers/net/ethernet/marvell/mvneta.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index d5f0d72..baa85af 100644
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c@@ -1391,6 +1391,8 @@ static int mvneta_rx(struct mvneta_port *pp, int rx_todo, { struct net_device *dev = pp->dev; int rx_done, rx_filled; + u32 rcvd_pkts = 0; + u32 rcvd_bytes = 0; /* Get number of received packets */ rx_done = mvneta_rxq_busy_desc_num_get(pp, rxq);
@@ -1428,10 +1430,8 @@ static int mvneta_rx(struct mvneta_port *pp, int rx_todo, rx_bytes = rx_desc->data_size - (ETH_FCS_LEN + MVNETA_MH_SIZE); - u64_stats_update_begin(&pp->rx_stats.syncp); - pp->rx_stats.packets++; - pp->rx_stats.bytes += rx_bytes; - u64_stats_update_end(&pp->rx_stats.syncp); + rcvd_pkts++; + rcvd_bytes += rx_bytes; /* Linux processing */ skb_reserve(skb, MVNETA_MH_SIZE);
@@ -1452,6 +1452,13 @@ static int mvneta_rx(struct mvneta_port *pp, int rx_todo, } } + if (rcvd_pkts) { + u64_stats_update_begin(&pp->rx_stats.syncp); + pp->rx_stats.packets += rcvd_pkts; + pp->rx_stats.bytes += rcvd_bytes; + u64_stats_update_end(&pp->rx_stats.syncp); + } + /* Update rxq management counters */ mvneta_rxq_desc_num_update(pp, rxq, rx_done, rx_filled);
--
1.7.12.2.21.g234cd45.dirty