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

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Message-ID: <CANn89i+Z6RiTGjzxMkd13iy-mP6OaZxo_hOuxVEr0x=+N=0nxA@mail.gmail.com>
Date: Mon, 17 Jul 2023 19:17:32 +0200
From: Eric Dumazet <edumazet@...gle.com>
To: Soheil Hassas Yeganeh <soheil@...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 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.