Re: [net v3 2/3] net: sched: add check tc_skip_classify in sch egress

On Tue, Nov 30, 2021 at 9:24 AM Tonghao Zhang [off-list ref] wrote:

On Tue, Nov 30, 2021 at 1:44 AM Eric Dumazet [off-list ref] wrote:

quoted

On Sun, Nov 28, 2021 at 8:55 PM [off-list ref] wrote:

quoted

From: Tonghao Zhang <redacted>

Try to resolve the issues as below:
* 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

  Before: 10662.33 tps, 108.95 Mbit/s
  After:  12434.48 tps, 145.89 Mbit/s
  For TCP_RR, there are 16.6% improvement, TCP_STREAM 33.9%.

These numbers mean nothing, really.

I think you should put 10,000 filters instead of 100 so that the
numbers look even better ?

This 100 filters with different prio, I will install 10,000 filters
and test again. Thanks.

Hi Eric
I install 10,000 filters with different prio: for example
tc filter add dev enp5s0f0 egress protocol ip prio 10000 flower
skip_hw src_ip 4.4.39.16 action mirred egress redirect dev ifb0

Test test commands:
taskset -c 1 netperf -t TCP_RR -L 4.4.39.16 -H 4.4.200.200 -- -r 32,32
taskset -c 1 netperf -t TCP_STREAM -L 4.4.39.16 -H 4.4.200.200 -- -m 32

Without patch:
152.04 tps
0.58 10^6bits/sec
With patch:
303.07 tps
1.51 10^6bits/sec

quoted

As a matter of fact, you add yet another check in fast  path.

For some reason I have not received the cover letter and patch 1/3.

1/3 patch, https://patchwork.kernel.org/project/netdevbpf/patch/20211129045503.20217-1-xiangxia.m.yue@gmail.com/


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Best regards, Tonghao

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Best regards, Tonghao