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Message-Id: <20211028135644.2258-1-xiangxia.m.yue@gmail.com>
Date: Thu, 28 Oct 2021 21:56:44 +0800
From: xiangxia.m.yue@...il.com
To: netdev@...r.kernel.org
Cc: Tonghao Zhang <xiangxia.m.yue@...il.com>,
Willem de Bruijn <willemb@...gle.com>,
Cong Wang <xiyou.wangcong@...il.com>,
Jakub Kicinski <kuba@...nel.org>
Subject: [PATCH] net: sched: check tc_skip_classify as far as possible
From: Tonghao Zhang <xiangxia.m.yue@...il.com>
We look up and then check tc_skip_classify flag in net
sched layer, even though skb don't want to be classified.
That case may consume a lot of cpu cycles.
Install the rules as below:
$ for id in $(seq 1 100); do
$ tc filter add ... egress prio $id ... action mirred egress redirect dev ifb0
$ done
netperf:
$ taskset -c 1 netperf -t TCP_RR -H ip -- -r 32,32
$ taskset -c 1 netperf -t TCP_STREAM -H ip -- -m 32
Without this patch:
10662.33 tps
108.95 Mbit/s
With this patch:
12434.48 tps
145.89 Mbit/s
For TCP_RR, there are 16.6% improvement, TCP_STREAM 33.9%.
Cc: Willem de Bruijn <willemb@...gle.com>
Cc: Cong Wang <xiyou.wangcong@...il.com>
Cc: Jakub Kicinski <kuba@...nel.org>
Signed-off-by: Tonghao Zhang <xiangxia.m.yue@...il.com>
---
net/core/dev.c | 3 ++-
net/sched/act_api.c | 3 ---
2 files changed, 2 insertions(+), 4 deletions(-)
diff --git a/net/core/dev.c b/net/core/dev.c
index eb61a8821b3a..856ac1fb75b4 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4155,7 +4155,8 @@ static int __dev_queue_xmit(struct sk_buff *skb, struct net_device *sb_dev)
#ifdef CONFIG_NET_CLS_ACT
skb->tc_at_ingress = 0;
# ifdef CONFIG_NET_EGRESS
- if (static_branch_unlikely(&egress_needed_key)) {
+ if (static_branch_unlikely(&egress_needed_key) &&
+ !skb_skip_tc_classify(skb)) {
skb = sch_handle_egress(skb, &rc, dev);
if (!skb)
goto out;
diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index 7dd3a2dc5fa4..bd66f27178be 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -722,9 +722,6 @@ int tcf_action_exec(struct sk_buff *skb, struct tc_action **actions,
int i;
int ret = TC_ACT_OK;
- if (skb_skip_tc_classify(skb))
- return TC_ACT_OK;
-
restart_act_graph:
for (i = 0; i < nr_actions; i++) {
const struct tc_action *a = actions[i];
--
2.27.0
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