net_sched: act_gact: remove spinlock in fast path
Final step for gact RCU operation :
1) Use percpu stats
2) update lastuse only every clock tick to avoid false sharing
3) Remove spinlock acquisition, as it is no longer needed.
Since this is the last contended lock in packet RX when tc gact is used,
this gives impressive gain.
My host with 8 RX queues was handling 5 Mpps before the patch,
and more than 11 Mpps after patch.
Tested:
On receiver :
dev=eth0
tc qdisc del dev $dev ingress 2>/dev/null
tc qdisc add dev $dev ingress
tc filter del dev $dev root pref 10 2>/dev/null
tc filter del dev $dev pref 10 2>/dev/null
tc filter add dev $dev est 1sec 4sec parent ffff: protocol ip prio 1 \
u32 match ip src 7.0.0.0/8 flowid 1:15 action drop
Sender sends packets flood from 7/8 network
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/act_api.h b/include/net/act_api.h
index db2063f..8d2a707 100644
--- a/include/net/act_api.h
+++ b/include/net/act_api.h
@@ -70,6 +70,17 @@
kfree(hf->htab);
}
+/* Update lastuse only if needed, to avoid dirtying a cache line.
+ * We use a temp variable to avoid fetching jiffies twice.
+ */
+static inline void tcf_lastuse_update(struct tcf_t *tm)
+{
+ unsigned long now = jiffies;
+
+ if (tm->lastuse != now)
+ tm->lastuse = now;
+}
+
#ifdef CONFIG_NET_CLS_ACT
#define ACT_P_CREATED 1
