Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
In-Reply-To: <CANn89iLN9H8tUhjMh1o0N7Ng8fPuXqQdpgkpBANpLwywaS3kNA@mail.gmail.com>
References: <1536462862-11767-1-git-send-email-laoar.shao@gmail.com>
 <1536462862-11767-2-git-send-email-laoar.shao@gmail.com> <CANn89iLN9H8tUhjMh1o0N7Ng8fPuXqQdpgkpBANpLwywaS3kNA@mail.gmail.com>
From:   Yafang Shao <laoar.shao@gmail.com>
Date:   Mon, 10 Sep 2018 18:56:33 +0800
Message-ID: <CALOAHbCYknwreEpmn-bV0HAXmkvcXR9CH4k9GHWChS2_NP8TGQ@mail.gmail.com>
Subject: Re: [PATCH v2 net-next 2/2] tcp: fix the error count of tcpInSegs
To:     Eric Dumazet <edumazet@google.com>
Cc:     David Miller <davem@davemloft.net>,
        netdev <netdev@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Mon, Sep 10, 2018 at 2:32 AM, Eric Dumazet <edumazet@google.com> wrote:
> On Sat, Sep 8, 2018 at 8:14 PM Yafang Shao <laoar.shao@gmail.com> wrote:
>>
>> In RFC1213, the tcpInSegs is the total number of segments received.
>> While currently it is the total number of SKBs received.
>> The number of SKBs may be not equal with the numer of segments because of
>> GRO.
>> So fix this error count.
>>
>
> We have discussed this in the past and the consensus was it was too
> late to change this.
>
> IP counters have the same issue, so after your patch, we would have
> quite a difference between transport and network layers.
>
> Adding all these max_t(u16, 1, skb_shinfo(skb)->gso_segs)) everywhere add a cost

May be we could give a comment here why we do it like this, otherwise
it may make a misunderstanding.

Thanks
Yafang