netdev - Re: [EXT] [PATCH net-next v4 0/3] net: atlantic: Add XDP support

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Message-ID: <dac72406-2743-ce1a-a0d7-4078e5d222be@marvell.com>
Date:   Wed, 13 Apr 2022 09:52:57 +0200
From:   Igor Russkikh <irusskikh@...vell.com>
To:     Taehee Yoo <ap420073@...il.com>, <davem@...emloft.net>,
        <kuba@...nel.org>, <pabeni@...hat.com>, <netdev@...r.kernel.org>,
        <ast@...nel.org>, <daniel@...earbox.net>, <hawk@...nel.org>,
        <john.fastabend@...il.com>, <andrii@...nel.org>, <kafai@...com>,
        <songliubraving@...com>, <yhs@...com>, <kpsingh@...nel.org>,
        <bpf@...r.kernel.org>
Subject: Re: [EXT] [PATCH net-next v4 0/3] net: atlantic: Add XDP support

> v4:
>  - Fix compile warning
> 
> v3:
>  - Change wrong PPS performance result 40% -> 80% in single
>    core(Intel i3-12100)
>  - Separate aq_nic_map_xdp() from aq_nic_map_skb()
>  - Drop multi buffer packets if single buffer XDP is attached
>  - Disable LRO when single buffer XDP is attached
>  - Use xdp_get_{frame/buff}_len()

Hi Taehee, thanks for taking care of that!

Reviewed-by: Igor Russkikh <irusskikh@...vell.com>

A small notice about the selection of 3K packet size for XDP.
Its a kind of compromise I think, because with common 1.4K MTU we'll get wasted
2K bytes minimum per packet.

I was thinking it would be possible to reuse the existing page flipping technique
together with higher page_order, to keep default 2K fragment size.
E.g.
( 256(xdp_head)+2K(pkt frag) ) x 3 (flips) = ~7K

Meaning we can allocate 8K (page_order=1) pages, and fit three xdp packets into each, wasting only 1K per three packets.

But its just kind of an idea for future optimization.

Regards,
  Igor