Messages in this thread Patch in this message | | | From | Asbjørn Sloth Tønnesen <> | Subject | [PATCH net-next 3/3] net: sched: make skip_sw actually skip software | Date | Thu, 15 Feb 2024 16:04:44 +0000 |
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TC filters come in 3 variants: - no flag (no opinion, process wherever possible) - skip_hw (do not process filter by hardware) - skip_sw (do not process filter by software)
However skip_sw is implemented so that the skip_sw flag can first be checked, after it has been matched.
IMHO it's common when using skip_sw, to use it on all rules.
So if all filters in a block is skip_sw filters, then we can bail early, we can thus avoid having to match the filters, just to check for the skip_sw flag.
+----------------------------+--------+--------+--------+ | Test description | Pre | Post | Rel. | | | kpps | kpps | chg. | +----------------------------+--------+--------+--------+ | basic forwarding + notrack | 1264.9 | 1277.7 | 1.01x | | switch to eswitch mode | 1067.1 | 1071.0 | 1.00x | | add ingress qdisc | 1056.0 | 1059.1 | 1.00x | +----------------------------+--------+--------+--------+ | 1 non-matching rule | 927.9 | 1057.1 | 1.14x | | 10 non-matching rules | 495.8 | 1055.6 | 2.13x | | 25 non-matching rules | 280.6 | 1053.5 | 3.75x | | 50 non-matching rules | 162.0 | 1055.7 | 6.52x | | 100 non-matching rules | 87.7 | 1019.0 | 11.62x | +----------------------------+--------+--------+--------+
perf top (100 n-m skip_sw rules - pre patch): 25.57% [kernel] [k] __skb_flow_dissect 20.77% [kernel] [k] rhashtable_jhash2 14.26% [kernel] [k] fl_classify 13.28% [kernel] [k] fl_mask_lookup 6.38% [kernel] [k] memset_orig 3.22% [kernel] [k] tcf_classify
perf top (100 n-m skip_sw rules - post patch): 4.28% [kernel] [k] __dev_queue_xmit 3.80% [kernel] [k] check_preemption_disabled 3.68% [kernel] [k] nft_do_chain 3.08% [kernel] [k] __netif_receive_skb_core.constprop.0 2.59% [kernel] [k] mlx5e_xmit 2.48% [kernel] [k] mlx5e_skb_from_cqe_mpwrq_nonlinear
Test setup: DUT: Intel Xeon D-1518 (2.20GHz) w/ Nvidia/Mellanox ConnectX-6 Dx 2x100G Data rate measured on switch (Extreme X690), and DUT connected as a router on a stick, with pktgen and pktsink as VLANs. Pktgen was in range 12.79 - 12.95 Mpps across all tests.
Signed-off-by: Asbjørn Sloth Tønnesen <ast@fiberby.net> --- include/net/pkt_cls.h | 5 +++++ net/core/dev.c | 3 +++ 2 files changed, 8 insertions(+)
diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h index a4ee43f493bb..a065da4df7ff 100644 --- a/include/net/pkt_cls.h +++ b/include/net/pkt_cls.h @@ -74,6 +74,11 @@ static inline bool tcf_block_non_null_shared(struct tcf_block *block) return block && block->index; } +static inline bool tcf_block_has_skip_sw_only(struct tcf_block *block) +{ + return block && atomic_read(&block->filtercnt) == atomic_read(&block->skipswcnt); +} + static inline struct Qdisc *tcf_block_q(struct tcf_block *block) { WARN_ON(tcf_block_shared(block)); diff --git a/net/core/dev.c b/net/core/dev.c index d8dd293a7a27..7cd014e5066e 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3910,6 +3910,9 @@ static int tc_run(struct tcx_entry *entry, struct sk_buff *skb, if (!miniq) return ret; + if (tcf_block_has_skip_sw_only(miniq->block)) + return ret; + tc_skb_cb(skb)->mru = 0; tc_skb_cb(skb)->post_ct = false; tcf_set_drop_reason(skb, *drop_reason); -- 2.43.0
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