From 3df97ba83019d524c012fd43d3216d4cc3005955 Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Mon, 25 Apr 2016 23:13:42 -0400 Subject: [PATCH] tuntap: calculate rps hash only when needed There's no need to calculate rps hash if it was not enabled. So this patch export rps_needed and check it before trying to get rps hash. Tests (using pktgen to inject packets to guest) shows this can improve pps about 13% (when rps is disabled). Before: ~1150000 pps After: ~1300000 pps Cc: Michael S. Tsirkin Signed-off-by: Jason Wang ---- Changes from V1: - Fix build when CONFIG_RPS is not set Signed-off-by: David S. Miller --- drivers/net/tun.c | 4 +++- net/core/dev.c | 1 + 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 42992dcbdda8..425e983bab93 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -833,7 +833,8 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) if (txq >= numqueues) goto drop; - if (numqueues == 1) { +#ifdef CONFIG_RPS + if (numqueues == 1 && static_key_false(&rps_needed)) { /* Select queue was not called for the skbuff, so we extract the * RPS hash and save it into the flow_table here. */ @@ -848,6 +849,7 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) tun_flow_save_rps_rxhash(e, rxhash); } } +#endif tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len); diff --git a/net/core/dev.c b/net/core/dev.c index e96a3bc2c634..c2f3d5dbde56 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3469,6 +3469,7 @@ u32 rps_cpu_mask __read_mostly; EXPORT_SYMBOL(rps_cpu_mask); struct static_key rps_needed __read_mostly; +EXPORT_SYMBOL(rps_needed); static struct rps_dev_flow * set_rps_cpu(struct net_device *dev, struct sk_buff *skb, -- 2.11.0