From: Oleksandr Natalenko <oleksandr@natalenko.name>
To: Eric Dumazet <edumazet@google.com>
Cc: Neal Cardwell <ncardwell@google.com>,
Eric Dumazet <eric.dumazet@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
Netdev <netdev@vger.kernel.org>,
Yuchung Cheng <ycheng@google.com>,
Soheil Hassas Yeganeh <soheil@google.com>,
Jerry Chu <hkchu@google.com>, Dave Taht <dave.taht@gmail.com>
Subject: Re: TCP and BBR: reproducibly low cwnd and bandwidth
Date: Fri, 16 Feb 2018 23:50:55 +0100 [thread overview]
Message-ID: <7409814.oObJlsYiIU@natalenko.name> (raw)
In-Reply-To: <CANn89iJ_P4AUKEVAzWYWd-4rk336zftDXSe_nCNxU3O7NqwrNQ@mail.gmail.com>
Hi.
On pátek 16. února 2018 21:54:05 CET Eric Dumazet wrote:
> /* snip */
> Something fishy really :
> /* snip */
> Not only the receiver suddenly adds a 25 ms delay, but also note that
> it acknowledges all prior segments (ack 112949), but with a wrong ecr
> value ( 2327043753 )
> instead of 2327043759
> /* snip */
Eric has encouraged me to look closer at what's there in the ethtool, and I've
just had a free time to play with it. I've found out that enabling scatter-
gather (ethtool -K enp3s0 sg on, it is disabled by default on both hosts)
brings the throughput back to normal even with BBR+fq_codel.
Whyyyy? What's the deal BBR has with sg?
Oleksandr
next prev parent reply other threads:[~2018-02-16 22:50 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-15 20:42 TCP and BBR: reproducibly low cwnd and bandwidth Oleksandr Natalenko
2018-02-16 15:15 ` Oleksandr Natalenko
2018-02-16 16:25 ` Eric Dumazet
2018-02-16 17:37 ` Oleksandr Natalenko
2018-02-16 16:26 ` Holger Hoffstätte
2018-02-16 16:56 ` Neal Cardwell
2018-02-16 17:13 ` Holger Hoffstätte
2018-02-16 17:35 ` Oleksandr Natalenko
2018-02-16 16:21 ` Eric Dumazet
[not found] ` <CADVnQymiswHBp32dcMvWd1WfYLpFqY4QTas8yABFQE7KKKc5ag@mail.gmail.com>
2018-02-16 16:43 ` Eric Dumazet
2018-02-16 16:45 ` Neal Cardwell
2018-02-16 17:00 ` Oleksandr Natalenko
2018-02-16 17:25 ` Oleksandr Natalenko
2018-02-16 17:56 ` Holger Hoffstätte
2018-02-16 19:54 ` Oleksandr Natalenko
2018-02-16 20:54 ` Eric Dumazet
2018-02-16 22:50 ` Eric Dumazet
2018-02-16 23:06 ` Oleksandr Natalenko
2018-02-16 22:50 ` Oleksandr Natalenko [this message]
2018-02-16 22:59 ` Eric Dumazet
2018-02-17 10:01 ` Oleksandr Natalenko
2018-02-17 18:52 ` Eric Dumazet
2018-02-18 21:04 ` Eric Dumazet
2018-02-18 21:06 ` Eric Dumazet
2018-02-18 21:49 ` Oleksandr Natalenko
2018-02-18 22:24 ` Eric Dumazet
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