netdev - Re: [PATCH net-next] tcp: get rid of sysctl_tcp_adv_win

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Message-ID: <CACSApvbVQ8uz9Rw1DG2aBUGAuTW75skYmC4B-B=WrAx3HcLPig@mail.gmail.com>
Date: Mon, 17 Jul 2023 13:20:20 -0400
From: Soheil Hassas Yeganeh <soheil@...gle.com>
To: Eric Dumazet <edumazet@...gle.com>
Cc: "David S . Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>, 
	Paolo Abeni <pabeni@...hat.com>, netdev@...r.kernel.org, 
	Neal Cardwell <ncardwell@...gle.com>, Yuchung Cheng <ycheng@...gle.com>, eric.dumazet@...il.com
Subject: Re: [PATCH net-next] tcp: get rid of sysctl_tcp_adv_win_scale

On Mon, Jul 17, 2023 at 1:17 PM Eric Dumazet <edumazet@...gle.com> wrote:
>
> On Mon, Jul 17, 2023 at 6:52 PM Soheil Hassas Yeganeh <soheil@...gle.com> wrote:
> >
> >
> > Should we use PAGE_SIZE instead of 4096?
>
> Great question. I thought of using 50%, but used this formula to kind
> of document the problem.
>
> Using PAGE_SIZE would probably hurt arches with large pages, for the
> initial round trip.
>
> Given that TCP normally uses IW10, there is almost no risk of tcp collapsing
> for the first RTT.

This is a very good point. No change needed then.  Thank you!