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authorJason Wang <jasowang@redhat.com>2016-04-25 23:13:42 -0400
committerDavid S. Miller <davem@davemloft.net>2016-04-28 16:38:54 -0400
commit3df97ba83019d524c012fd43d3216d4cc3005955 (patch)
treed913793fb00287a9e120f36d9a6d274a0257c2f4
parentf345c9a5726d10cc3613d17ae75dcb1ab0986ba1 (diff)
downloadlinux-3df97ba83019d524c012fd43d3216d4cc3005955.tar.gz
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 <mst@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com> ---- Changes from V1: - Fix build when CONFIG_RPS is not set Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/tun.c4
-rw-r--r--net/core/dev.c1
2 files changed, 4 insertions, 1 deletions
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,