Re: [PATCH v2 net-next 00/14] net_sched: speedup qdisc dequeue

["Toke Høiland-Jørgensen" <toke@redhat.com>]

Eric Dumazet <edumazet@google.com> writes:

> Avoid up to two cache line misses in qdisc dequeue() to fetch
> skb_shinfo(skb)->gso_segs/gso_size while qdisc spinlock is held.
>
> Idea is to cache gso_segs at enqueue time before spinlock is
> acquired, in the first skb cache line, where we already
> have qdisc_skb_cb(skb)->pkt_len.
>
> This series gives a 8 % improvement in a TX intensive workload.
>
> (120 Mpps -> 130 Mpps on a Turin host, IDPF with 32 TX queues)
>
> v2: - Fixed issues reported by Jakub (thanks !)
>     - Added three patches adding/using qdisc_dequeue_drop() after
>       recent regressions with CAKE qdisc reported by Toke.
>       More fixes to come later.
>
> v1: https://lore.kernel.org/netdev/20251110094505.3335073-1-edumazet@google.com/T/#m8f562ed148f807c02fd02c6cd243604d449615b9
>
> Eric Dumazet (14):
>   net_sched: make room for (struct qdisc_skb_cb)->pkt_segs
>   net: init shinfo->gso_segs from qdisc_pkt_len_init()
>   net_sched: initialize qdisc_skb_cb(skb)->pkt_segs in
>     qdisc_pkt_len_init()
>   net: use qdisc_pkt_len_segs_init() in sch_handle_ingress()
>   net_sched: use qdisc_skb_cb(skb)->pkt_segs in bstats_update()
>   net_sched: cake: use qdisc_pkt_segs()
>   net_sched: add Qdisc_read_mostly and Qdisc_write groups
>   net_sched: sch_fq: move qdisc_bstats_update() to fq_dequeue_skb()
>   net_sched: sch_fq: prefetch one skb ahead in dequeue()
>   net: prefech skb->priority in __dev_xmit_skb()
>   net: annotate a data-race in __dev_xmit_skb()
>   net_sched: add tcf_kfree_skb_list() helper
>   net_sched: add qdisc_dequeue_drop() helper
>   net_sched: use qdisc_dequeue_drop() in cake, codel, fq_codel

As mentioned in the other thread[0], I tested this series and it
definitely seems to improve things, so feel free to add my:

Tested-by: Toke Høiland-Jørgensen <toke@redhat.com>