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Message-ID: <353b5206205cc71d25998c9601a052dade081b94.camel@redhat.com>
Subject: Re: [PATCH net-next 00/11] UDP/IPv6 refactoring
From:   Paolo Abeni <pabeni@redhat.com>
To:     Pavel Begunkov <asml.silence@gmail.com>, netdev@vger.kernel.org,
        "David S . Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>
Cc:     David Ahern <dsahern@kernel.org>,
        Eric Dumazet <edumazet@google.com>,
        linux-kernel@vger.kernel.org
Date:   Thu, 28 Apr 2022 16:04:28 +0200
In-Reply-To: <cover.1651071843.git.asml.silence@gmail.com>
References: <cover.1651071843.git.asml.silence@gmail.com>
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On Thu, 2022-04-28 at 11:56 +0100, Pavel Begunkov wrote:
> Refactor UDP/IPv6 and especially udpv6_sendmsg() paths. The end result looks
> cleaner than it was before and the series also removes a bunch of instructions
> and other overhead from the hot path positively affecting performance.
> 
> It was a part of a larger series, there were some perf numbers for it, see
> https://lore.kernel.org/netdev/cover.1648981570.git.asml.silence@gmail.com/
> 
> Pavel Begunkov (11):
>   ipv6: optimise ipcm6 cookie init
>   udp/ipv6: refactor udpv6_sendmsg udplite checks
>   udp/ipv6: move pending section of udpv6_sendmsg
>   udp/ipv6: prioritise the ip6 path over ip4 checks
>   udp/ipv6: optimise udpv6_sendmsg() daddr checks
>   udp/ipv6: optimise out daddr reassignment
>   udp/ipv6: clean up udpv6_sendmsg's saddr init
>   ipv6: partially inline fl6_update_dst()
>   ipv6: refactor opts push in __ip6_make_skb()
>   ipv6: improve opt-less __ip6_make_skb()
>   ipv6: clean up ip6_setup_cork
> 
>  include/net/ipv6.h    |  24 +++----
>  net/ipv6/datagram.c   |   4 +-
>  net/ipv6/exthdrs.c    |  15 ++--
>  net/ipv6/ip6_output.c |  53 +++++++-------
>  net/ipv6/raw.c        |   8 +--
>  net/ipv6/udp.c        | 158 ++++++++++++++++++++----------------------
>  net/l2tp/l2tp_ip6.c   |   8 +--
>  7 files changed, 122 insertions(+), 148 deletions(-)

Just a general comment here: IMHO the above diffstat is quite
significant and some patches looks completely non trivial to me.

I think we need a quite significant performance gain to justify the
above, could you please share your performace data, comprising the
testing scenario?

Thanks!

Paolo