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net: mvneta: increase the 64-bit rx/tx stats out of the hot path 

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 <thomas.petazzoni@free-electrons.com>
Cc: Gregory CLEMENT <gregory.clement@free-electrons.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Tested-by: Arnaud Ebalard <arno@natisbad.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
willy tarreau 2014-01-16 08:20:07 +01:00 committed by David S. Miller
parent a81ab36bf5
commit dc4277dd41
1 changed files with 11 additions and 4 deletions
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15
drivers/net/ethernet/marvell/mvneta.c
View File

@ -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);