Re: [net-next v11 2/2] net: sched: support hash selecting tx queue
flat view
From: Dave Taht <hidden>
Date: 2022-03-23 18:10:27
On Wed, Mar 23, 2022 at 11:45 AM [off-list ref] wrote:
From: Tonghao Zhang <redacted>
This patch allows users to pick queue_mapping, range
from A to B. Then we can load balance packets from A
to B tx queue. The range is an unsigned 16bit value
in decimal format.
$ tc filter ... action skbedit queue_mapping skbhash A B
"skbedit queue_mapping QUEUE_MAPPING" (from "man 8 tc-skbedit")
is enhanced with flags: SKBEDIT_F_TXQ_SKBHASH
+----+ +----+ +----+
| P1 | | P2 | | Pn |
+----+ +----+ +----+
| | |
+-----------+-----------+
|
| clsact/skbedit
| MQ
v
+-----------+-----------+
| q0 | qn | qm
v v v
HTB/FQ FIFO ... FIFO
For example:
If P1 sends out packets to different Pods on other host, and
we want distribute flows from qn - qm. Then we can use skb->hash
as hash.
setup commands:
$ NETDEV=eth0
$ ip netns add n1
$ ip link add ipv1 link $NETDEV type ipvlan mode l2
$ ip link set ipv1 netns n1
$ ip netns exec n1 ifconfig ipv1 2.2.2.100/24 up
$ tc qdisc add dev $NETDEV clsact
$ tc filter add dev $NETDEV egress protocol ip prio 1 \
flower skip_hw src_ip 2.2.2.100 action skbedit queue_mapping skbhash 2 6
$ tc qdisc add dev $NETDEV handle 1: root mq
$ tc qdisc add dev $NETDEV parent 1:1 handle 2: htb
$ tc class add dev $NETDEV parent 2: classid 2:1 htb rate 100kbit
$ tc class add dev $NETDEV parent 2: classid 2:2 htb rate 200kbit
$ tc qdisc add dev $NETDEV parent 1:2 tbf rate 100mbit burst 100mb latency 1aside from the utility of this patch the above example settings for burst and latency are a bit awkward.
$ tc qdisc add dev $NETDEV parent 1:3 pfifo $ tc qdisc add dev $NETDEV parent 1:4 pfifo $ tc qdisc add dev $NETDEV parent 1:5 pfifo $ tc qdisc add dev $NETDEV parent 1:6 pfifo $ tc qdisc add dev $NETDEV parent 1:7 pfifo
pfifo's default packet limit is 1000 packets, 5 queues like this could create about 650ms of latency with tbf, more with htb & gso.
$ ip netns exec n1 iperf3 -c 2.2.2.1 -i 1 -t 10 -P 10
Given the structure of this test, you are probably more regulated by tsq than pfifo, however a packet capture of the actual tcp rtt induced would be interesting. substitute fq_codel for pfifo, also. It's great to send lots of packets over lots of queues, but not so great to have seconds of data outstanding in them.
quoted hunk ↗ jump to hunk
pick txqueue from 2 - 6: $ ethtool -S $NETDEV | grep -i tx_queue_[0-9]_bytes tx_queue_0_bytes: 42 tx_queue_1_bytes: 0 tx_queue_2_bytes: 11442586444 tx_queue_3_bytes: 7383615334 tx_queue_4_bytes: 3981365579 tx_queue_5_bytes: 3983235051 tx_queue_6_bytes: 6706236461 tx_queue_7_bytes: 42 tx_queue_8_bytes: 0 tx_queue_9_bytes: 0 txqueues 2 - 6 are mapped to classid 1:3 - 1:7 $ tc -s class show dev $NETDEV ... class mq 1:3 root leaf 8002: Sent 11949133672 bytes 7929798 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 class mq 1:4 root leaf 8003: Sent 7710449050 bytes 5117279 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 class mq 1:5 root leaf 8004: Sent 4157648675 bytes 2758990 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 class mq 1:6 root leaf 8005: Sent 4159632195 bytes 2759990 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 class mq 1:7 root leaf 8006: Sent 7003169603 bytes 4646912 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 ... Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Cong Wang <redacted> Cc: Jiri Pirko <jiri@resnulli.us> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Jonathan Lemon <redacted> Cc: Eric Dumazet <redacted> Cc: Alexander Lobakin <redacted> Cc: Paolo Abeni <pabeni@redhat.com> Cc: Talal Ahmad <redacted> Cc: Kevin Hao <redacted> Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org> Cc: Kees Cook <redacted> Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com> Cc: Antoine Tenart <atenart@kernel.org> Cc: Wei Wang <redacted> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Tonghao Zhang <redacted> Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com> --- include/net/tc_act/tc_skbedit.h | 1 + include/uapi/linux/tc_act/tc_skbedit.h | 2 ++ net/sched/act_skbedit.c | 49 ++++++++++++++++++++++++-- 3 files changed, 50 insertions(+), 2 deletions(-)diff --git a/include/net/tc_act/tc_skbedit.h b/include/net/tc_act/tc_skbedit.h index 00bfee70609e..ee96e0fa6566 100644 --- a/include/net/tc_act/tc_skbedit.h +++ b/include/net/tc_act/tc_skbedit.h@@ -17,6 +17,7 @@ struct tcf_skbedit_params { u32 mark; u32 mask; u16 queue_mapping; + u16 mapping_mod; u16 ptype; struct rcu_head rcu; };diff --git a/include/uapi/linux/tc_act/tc_skbedit.h b/include/uapi/linux/tc_act/tc_skbedit.h index 800e93377218..6cb6101208d0 100644 --- a/include/uapi/linux/tc_act/tc_skbedit.h +++ b/include/uapi/linux/tc_act/tc_skbedit.h@@ -29,6 +29,7 @@ #define SKBEDIT_F_PTYPE 0x8 #define SKBEDIT_F_MASK 0x10 #define SKBEDIT_F_INHERITDSFIELD 0x20 +#define SKBEDIT_F_TXQ_SKBHASH 0x40 struct tc_skbedit { tc_gen;@@ -45,6 +46,7 @@ enum { TCA_SKBEDIT_PTYPE, TCA_SKBEDIT_MASK, TCA_SKBEDIT_FLAGS, + TCA_SKBEDIT_QUEUE_MAPPING_MAX, __TCA_SKBEDIT_MAX }; #define TCA_SKBEDIT_MAX (__TCA_SKBEDIT_MAX - 1)diff --git a/net/sched/act_skbedit.c b/net/sched/act_skbedit.c index d5799b4fc499..2634c725bc75 100644 --- a/net/sched/act_skbedit.c +++ b/net/sched/act_skbedit.c@@ -23,6 +23,20 @@ static unsigned int skbedit_net_id; static struct tc_action_ops act_skbedit_ops; +static u16 tcf_skbedit_hash(struct tcf_skbedit_params *params, + struct sk_buff *skb) +{ + u16 queue_mapping = params->queue_mapping; + + if (params->flags & SKBEDIT_F_TXQ_SKBHASH) { + u32 hash = skb_get_hash(skb); + + queue_mapping += hash % params->mapping_mod; + } + + return netdev_cap_txqueue(skb->dev, queue_mapping); +} + static int tcf_skbedit_act(struct sk_buff *skb, const struct tc_action *a, struct tcf_result *res) {@@ -62,7 +76,7 @@ static int tcf_skbedit_act(struct sk_buff *skb, const struct tc_action *a, #ifdef CONFIG_NET_EGRESS netdev_xmit_skip_txqueue(true); #endif - skb_set_queue_mapping(skb, params->queue_mapping); + skb_set_queue_mapping(skb, tcf_skbedit_hash(params, skb)); } if (params->flags & SKBEDIT_F_MARK) { skb->mark &= ~params->mask;@@ -96,6 +110,7 @@ static const struct nla_policy skbedit_policy[TCA_SKBEDIT_MAX + 1] = { [TCA_SKBEDIT_PTYPE] = { .len = sizeof(u16) }, [TCA_SKBEDIT_MASK] = { .len = sizeof(u32) }, [TCA_SKBEDIT_FLAGS] = { .len = sizeof(u64) }, + [TCA_SKBEDIT_QUEUE_MAPPING_MAX] = { .len = sizeof(u16) }, }; static int tcf_skbedit_init(struct net *net, struct nlattr *nla,@@ -112,6 +127,7 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla, struct tcf_skbedit *d; u32 flags = 0, *priority = NULL, *mark = NULL, *mask = NULL; u16 *queue_mapping = NULL, *ptype = NULL; + u16 mapping_mod = 1; bool exists = false; int ret = 0, err; u32 index;@@ -157,6 +173,25 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla, if (tb[TCA_SKBEDIT_FLAGS] != NULL) { u64 *pure_flags = nla_data(tb[TCA_SKBEDIT_FLAGS]); + if (*pure_flags & SKBEDIT_F_TXQ_SKBHASH) { + u16 *queue_mapping_max; + + if (!tb[TCA_SKBEDIT_QUEUE_MAPPING] || + !tb[TCA_SKBEDIT_QUEUE_MAPPING_MAX]) { + NL_SET_ERR_MSG_MOD(extack, "Missing required range of queue_mapping."); + return -EINVAL; + } + + queue_mapping_max = + nla_data(tb[TCA_SKBEDIT_QUEUE_MAPPING_MAX]); + if (*queue_mapping_max < *queue_mapping) { + NL_SET_ERR_MSG_MOD(extack, "The range of queue_mapping is invalid, max < min."); + return -EINVAL; + } + + mapping_mod = *queue_mapping_max - *queue_mapping + 1; + flags |= SKBEDIT_F_TXQ_SKBHASH; + } if (*pure_flags & SKBEDIT_F_INHERITDSFIELD) flags |= SKBEDIT_F_INHERITDSFIELD; }@@ -208,8 +243,10 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla, params_new->flags = flags; if (flags & SKBEDIT_F_PRIORITY) params_new->priority = *priority; - if (flags & SKBEDIT_F_QUEUE_MAPPING) + if (flags & SKBEDIT_F_QUEUE_MAPPING) { params_new->queue_mapping = *queue_mapping; + params_new->mapping_mod = mapping_mod; + } if (flags & SKBEDIT_F_MARK) params_new->mark = *mark; if (flags & SKBEDIT_F_PTYPE)@@ -276,6 +313,13 @@ static int tcf_skbedit_dump(struct sk_buff *skb, struct tc_action *a, goto nla_put_failure; if (params->flags & SKBEDIT_F_INHERITDSFIELD) pure_flags |= SKBEDIT_F_INHERITDSFIELD; + if (params->flags & SKBEDIT_F_TXQ_SKBHASH) { + if (nla_put_u16(skb, TCA_SKBEDIT_QUEUE_MAPPING_MAX, + params->queue_mapping + params->mapping_mod - 1)) + goto nla_put_failure; + + pure_flags |= SKBEDIT_F_TXQ_SKBHASH; + } if (pure_flags != 0 && nla_put(skb, TCA_SKBEDIT_FLAGS, sizeof(pure_flags), &pure_flags)) goto nla_put_failure;@@ -325,6 +369,7 @@ static size_t tcf_skbedit_get_fill_size(const struct tc_action *act) return nla_total_size(sizeof(struct tc_skbedit)) + nla_total_size(sizeof(u32)) /* TCA_SKBEDIT_PRIORITY */ + nla_total_size(sizeof(u16)) /* TCA_SKBEDIT_QUEUE_MAPPING */ + + nla_total_size(sizeof(u16)) /* TCA_SKBEDIT_QUEUE_MAPPING_MAX */ + nla_total_size(sizeof(u32)) /* TCA_SKBEDIT_MARK */ + nla_total_size(sizeof(u16)) /* TCA_SKBEDIT_PTYPE */ + nla_total_size(sizeof(u32)) /* TCA_SKBEDIT_MASK */ --2.27.0
-- I tried to build a better future, a few times: https://wayforward.archive.org/?site=https%3A%2F%2Fwww.icei.org Dave Täht CEO, TekLibre, LLC