netdev - Re: [PATCH net-next] tcp: force a PSH flag on TSO packets

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Message-ID: <CAJ3xEMhh=Ow-fZqnPtxUyZsCN89dRmy=NcaO+iK+iZZYBdZbqA@mail.gmail.com>
Date:   Thu, 19 Sep 2019 15:17:54 +0300
From:   Or Gerlitz <gerlitz.or@...il.com>
To:     Eric Dumazet <edumazet@...gle.com>
Cc:     "David S . Miller" <davem@...emloft.net>,
        netdev <netdev@...r.kernel.org>,
        Eric Dumazet <eric.dumazet@...il.com>,
        Soheil Hassas Yeganeh <soheil@...gle.com>,
        Neal Cardwell <ncardwell@...gle.com>,
        Yuchung Cheng <ycheng@...gle.com>,
        Daniel Borkmann <daniel@...earbox.net>,
        Tariq Toukan <tariqt@...lanox.com>
Subject: Re: [PATCH net-next] tcp: force a PSH flag on TSO packets

On Wed, Sep 11, 2019 at 12:54 AM Eric Dumazet <edumazet@...gle.com> wrote:
> When tcp sends a TSO packet, adding a PSH flag on it
> reduces the sojourn time of GRO packet in GRO receivers.
>
> This is particularly the case under pressure, since RX queues
> receive packets for many concurrent flows.
>
> A sender can give a hint to GRO engines when it is
> appropriate to flush a super-packet, especially when pacing

Hi Eric,

Is this correct that we add here the push flag for the tcp header template
from which all the tcp headers for SW GSO packets will be generated?

Wouldn't that cause a too early flush on GRO engines at the receiver side?

Or.