netdev - Re: [PATCH v2 net-next 2/6] net: add add indirect call wrapper in skb_release_head

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Message-ID: <c09e552f-883a-4e23-aaf0-5626071524bc@intel.com>
Date: Wed, 15 Oct 2025 15:08:06 +0200
From: Alexander Lobakin <aleksander.lobakin@...el.com>
To: Eric Dumazet <edumazet@...gle.com>
CC: "David S . Miller" <davem@...emloft.net>, Jakub Kicinski
	<kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, Simon Horman
	<horms@...nel.org>, Jamal Hadi Salim <jhs@...atatu.com>, Cong Wang
	<xiyou.wangcong@...il.com>, Jiri Pirko <jiri@...nulli.us>, Kuniyuki Iwashima
	<kuniyu@...gle.com>, Willem de Bruijn <willemb@...gle.com>,
	<netdev@...r.kernel.org>, <eric.dumazet@...il.com>
Subject: Re: [PATCH v2 net-next 2/6] net: add add indirect call wrapper in
 skb_release_head_state()

From: Eric Dumazet <edumazet@...gle.com>
Date: Wed, 15 Oct 2025 06:01:40 -0700

> On Wed, Oct 15, 2025 at 5:54 AM Alexander Lobakin
> <aleksander.lobakin@...el.com> wrote:
> 
>> You asked *me* to show the difference, in the orig discussion there's a
>> patch, there are tests and there is difference... :D
> 
> I am afraid I have not seen this.
> 
> The only thing I found was :
> 
> <quote>
> Not sure, but maybe we could add generic XSk skb destructor here as
> well? Or it's not that important as generic XSk is not the best way to
> use XDP sockets?
> 
> Maciej, what do you think?
> </quote>
> 
> No numbers.

>From [0]:

From: Jason Xing <kerneljasonxing@...il.com>
Date: Thu, 9 Oct 2025 16:37:56 +0800

> On Wed, Oct 8, 2025 at 3:42 AM Maciej Fijalkowski
> <maciej.fijalkowski@...el.com> wrote:
>>

[...]

>>> Not sure, but maybe we could add generic XSk skb destructor here as
>>> well?
>
> I added the following snippet[1] and only saw a stable ~1% improvement
> when sending 64 size packets with xdpsock.
>
> I'm not so sure it deserves a follow-up patch to Eric's series. Better
> than nothing? Any ideas on this one?
>
> [1]
> INDIRECT_CALL_4(skb->destructor, tcp_wfree, __sock_wfree, sock_wfree,
> xsk_destruct_skb, skb);
>
>>>  Or it's not that important as generic XSk is not the best way to
>>> use XDP sockets?
>
> Yes, it surely matters. At least, virtio_net and veth need this copy
> mode. And I've been working on batch xmit to ramp up the generic path.
>
>>>
>>> Maciej, what do you think?
>>
>> I would appreciate it as there has been various attempts to optmize
>> xsk generic xmit path.
>
> So do I!
>
> Thanks,
> Jason

[0]
https://lore.kernel.org/netdev/CAL+tcoBN9puWX-sTGvTiBN0Hg5oXKR3mjv783YXeR4Bsovuxkw@mail.gmail.com

Thanks,
Olek