netdev - Re: resend: tcp: performance issue with fastopen connections (mss

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Date:   Wed, 18 Jan 2017 09:35:43 -0800
From:   Eric Dumazet <edumazet@...gle.com>
To:     Alexey Kodanev <alexey.kodanev@...cle.com>
Cc:     Eric Dumazet <eric.dumazet@...il.com>,
        David Miller <davem@...emloft.net>,
        netdev <netdev@...r.kernel.org>,
        Vasily Isaenko <vasily.isaenko@...cle.com>,
        Neal Cardwell <ncardwell@...gle.com>,
        Yuchung Cheng <ycheng@...gle.com>
Subject: Re: resend: tcp: performance issue with fastopen connections (mss > window)

On Wed, Jan 18, 2017 at 9:32 AM, Alexey Kodanev
<alexey.kodanev@...cle.com> wrote:
> Hi Eric,
>
> On 01/13/2017 08:07 PM, Alexey Kodanev wrote:
>

> Looks like max_window not correctly initialized for tfo sockets.
> On my test machine it has set to '5592320' in tcp_fastopen_create_child().
>
> This diff fixes the issue, the question: is this the right place to do it?
>
> diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c
> index 4e777a3..33ed508 100644
> --- a/net/ipv4/tcp_fastopen.c
> +++ b/net/ipv4/tcp_fastopen.c
> @@ -206,6 +206,8 @@ static struct sock *tcp_fastopen_create_child(struct
> sock *sk,
>          */
>         tp->snd_wnd = ntohs(tcp_hdr(skb)->window);
>
> +       tp->max_window = tp->snd_wnd;
> +

Excellent catch. Let me test our regression tests with this.

Thanks !