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From: Neal Cardwell <ncardwell@google.com>
To: V JobNickname <workofv@gmail.com>
Cc: Netdev <netdev@vger.kernel.org>
Subject: Re: Is 3.18 patch "The tcp: TSO packets automatic sizing" will cause to Troughput drop when enable NO_HZ_IDEL or HIGH_RES_TIMERS ?
Date: Tue, 6 May 2014 12:48:27 -0400	[thread overview]
Message-ID: <CADVnQy=1WdUT1xHX04uBQtROwOYDZF6idw1Qx2o2DM13kWWjFQ@mail.gmail.com> (raw)
In-Reply-To: <CANHbGWs=oQBDVVZc8h5wX0WY+PRbQfCqiv5FrF1tH29QGiRndA@mail.gmail.com>

On Tue, May 6, 2014 at 12:17 PM, V JobNickname <workofv@gmail.com> wrote:
> More detail trace, the first commit of 3.10.18, tcp: TSO packets
> automatic sizing, cause to this issue.
> https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/diff/?id=5e25ba5003ee5de0ba2be56bfd54d16d4b1b028d

To provide another data point, it would be interesting to know what
performance you see with v3.15-rc4. Linux 3.15 has the following
patch:

 740b0f1841f6  tcp: switch rtt estimations to usec resolution

That patch switches tcp_update_pacing_rate() to use microsecond RTTs
for its calculation. That may help things in your case. (As Eric says,
more details would help.)

> I don't know why this TSO patch affect my network since the network
> driver doesn't enable NETIF_F_TSO.

Keep in mind that anytime the Linux TCP code or commit descriptions
talk about "TSO", the same applies to GSO. Is GSO enabled for your
device?

neal

  parent reply	other threads:[~2014-05-06 16:48 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-05-06 16:17 Is 3.18 patch "The tcp: TSO packets automatic sizing" will cause to Troughput drop when enable NO_HZ_IDEL or HIGH_RES_TIMERS ? V JobNickname
2014-05-06 16:30 ` Eric Dumazet
2014-05-06 16:41   ` Eric Dumazet
2014-05-07 14:27     ` V JobNickname
2014-05-07 14:33       ` David Laight
2014-05-07 15:45       ` Eric Dumazet
2014-05-07 16:18         ` V JobNickname
2014-05-06 16:48 ` Neal Cardwell [this message]
2014-05-07 15:51   ` V JobNickname
2014-05-07 16:25     ` Eric Dumazet
2014-05-07 16:28       ` Eric Dumazet
2014-05-08  5:48       ` V JobNickname

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