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

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Date:   Wed, 18 Jan 2017 10:13:26 -0800
From:   Yuchung Cheng <ycheng@...gle.com>
To:     Eric Dumazet <edumazet@...gle.com>
Cc:     Alexey Kodanev <alexey.kodanev@...cle.com>,
        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>
Subject: Re: resend: tcp: performance issue with fastopen connections (mss > window)

On Wed, Jan 18, 2017 at 9:35 AM, Eric Dumazet <edumazet@...gle.com> wrote:
>
> 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.
Indeed nice catch. Thanks for the investigative work!

>
> Thanks !