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From: Neal Cardwell <ncardwell@google.com>
To: Eric Dumazet <edumazet@google.com>
Cc: David Miller <davem@davemloft.net>,
	Netdev <netdev@vger.kernel.org>,
	jean-louis@dupond.be, Yuchung Cheng <ycheng@google.com>,
	Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: [PATCH net-next 2/3] tcp: implement coalescing on backlog queue
Date: Thu, 22 Nov 2018 13:01:36 -0500	[thread overview]
Message-ID: <CADVnQykiiFz5H3J_vrCXHQ_FQ+Fg3qCZKoynsc_fdY_PcTx8cg@mail.gmail.com> (raw)
In-Reply-To: <20181121175240.6075-3-edumazet@google.com>

On Wed, Nov 21, 2018 at 12:52 PM Eric Dumazet <edumazet@google.com> wrote:
>
> In case GRO is not as efficient as it should be or disabled,
> we might have a user thread trapped in __release_sock() while
> softirq handler flood packets up to the point we have to drop.
>
> This patch balances work done from user thread and softirq,
> to give more chances to __release_sock() to complete its work.
>
> This also helps if we receive many ACK packets, since GRO
> does not aggregate them.

Would this coalesce duplicate incoming ACK packets? Is there a risk
that this would eliminate incoming dupacks needed for fast recovery in
non-SACK connections? Perhaps pure ACKs should only be coalesced if
the ACK field is different?

neal

  parent reply	other threads:[~2018-11-23  4:42 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-21 17:52 [PATCH net-next 0/3] tcp: take a bit more care of backlog stress Eric Dumazet
2018-11-21 17:52 ` [PATCH net-next 1/3] tcp: remove hdrlen argument from tcp_queue_rcv() Eric Dumazet
2018-11-21 22:41   ` Yuchung Cheng
2018-11-21 17:52 ` [PATCH net-next 2/3] tcp: implement coalescing on backlog queue Eric Dumazet
2018-11-21 22:31   ` Yuchung Cheng
2018-11-21 22:40     ` Eric Dumazet
2018-11-22 16:34       ` Yuchung Cheng
2018-11-22 18:01   ` Neal Cardwell [this message]
2018-11-22 18:16     ` Eric Dumazet
2018-11-22 18:21       ` Eric Dumazet
2018-11-21 17:52 ` [PATCH net-next 3/3] tcp: implement head drops in " Eric Dumazet
2018-11-21 22:40   ` Yuchung Cheng
2018-11-21 22:47     ` Eric Dumazet
2018-11-21 23:46       ` Yuchung Cheng
2018-11-21 23:52         ` Eric Dumazet
2018-11-22  0:18           ` Eric Dumazet
2018-11-22  0:54             ` Yuchung Cheng
2018-11-22  1:01               ` Eric Dumazet
2018-11-23 19:25 ` [PATCH net-next 0/3] tcp: take a bit more care of backlog stress David Miller
2018-11-23 19:27   ` Eric Dumazet
2019-04-07 21:28 [PATCH net-next 2/3] tcp: implement coalescing on backlog queue richard.purdie
2019-04-24 14:51 ` Bruno Prémont
2019-04-24 15:47   ` Eric Dumazet
2019-04-25  7:55     ` Bruno Prémont
2019-04-25 13:13       ` Bruno Prémont
2019-04-25 13:30         ` Eric Dumazet
2019-04-25 14:16           ` Bruno Prémont

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