From fcbeb976d7ce783fd58e63e61c196d9a8912b3be Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 5 Oct 2014 10:11:27 -0700 Subject: [PATCH] net: introduce netdevice gso_min_segs attribute Some TSO engines might have a too heavy setup cost, that impacts performance on hosts sending small bursts (2 MSS per packet). This patch adds a device gso_min_segs, allowing drivers to set a minimum segment size for TSO packets, according to the NIC performance. Tested on a mlx4 NIC, this allows to get a ~110% increase of throughput when sending 2 MSS per packet. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/linux/netdevice.h | 4 +++- net/core/dev.c | 9 ++++++--- 2 files changed, 9 insertions(+), 4 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 22d54b9b700d..2df86f50261c 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1416,6 +1416,8 @@ enum netdev_priv_flags { * @gso_max_size: Maximum size of generic segmentation offload * @gso_max_segs: Maximum number of segments that can be passed to the * NIC for GSO + * @gso_min_segs: Minimum number of segments that can be passed to the + * NIC for GSO * * @dcbnl_ops: Data Center Bridging netlink ops * @num_tc: Number of traffic classes in the net device @@ -1666,7 +1668,7 @@ struct net_device { unsigned int gso_max_size; #define GSO_MAX_SEGS 65535 u16 gso_max_segs; - + u16 gso_min_segs; #ifdef CONFIG_DCB const struct dcbnl_rtnl_ops *dcbnl_ops; #endif diff --git a/net/core/dev.c b/net/core/dev.c index 7d5691cc1f47..c1a4de275576 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2567,10 +2567,12 @@ static netdev_features_t harmonize_features(struct sk_buff *skb, netdev_features_t netif_skb_features(struct sk_buff *skb) { + const struct net_device *dev = skb->dev; + netdev_features_t features = dev->features; + u16 gso_segs = skb_shinfo(skb)->gso_segs; __be16 protocol = skb->protocol; - netdev_features_t features = skb->dev->features; - if (skb_shinfo(skb)->gso_segs > skb->dev->gso_max_segs) + if (gso_segs > dev->gso_max_segs || gso_segs < dev->gso_min_segs) features &= ~NETIF_F_GSO_MASK; if (protocol == htons(ETH_P_8021Q) || protocol == htons(ETH_P_8021AD)) { @@ -2581,7 +2583,7 @@ netdev_features_t netif_skb_features(struct sk_buff *skb) } features = netdev_intersect_features(features, - skb->dev->vlan_features | + dev->vlan_features | NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_STAG_TX); @@ -6661,6 +6663,7 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name, dev->gso_max_size = GSO_MAX_SIZE; dev->gso_max_segs = GSO_MAX_SEGS; + dev->gso_min_segs = 0; INIT_LIST_HEAD(&dev->napi_list); INIT_LIST_HEAD(&dev->unreg_list); -- 2.11.0