From: Thomas Glanzmann <thomas@glanzmann.de>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>,
"David S. Miller" <davem@davemloft.net>,
"Nicholas A. Bellinger" <nab@linux-iscsi.org>,
target-devel <target-devel@vger.kernel.org>,
Linux Network Development <netdev@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] tcp: disable auto corking by default
Date: Sat, 8 Feb 2014 17:55:39 +0100 [thread overview]
Message-ID: <20140208165539.GA22359@glanzmann.de> (raw)
In-Reply-To: <1391871850.10160.103.camel@edumazet-glaptop2.roam.corp.google.com>
Hello Eric,
> > Disable auto corking by default
> We should let auto corking on during 3.14 development cycle so that we
> can fix the bugs, and thing of some optimizations.
I agree that leaving it enabled helps to find bugs, however I'm not
happy with the round trip time degradation.
> auto cork gives a strong incentive to applications to use
> TCP_CORK/MSG_MORE to avoid overhead of sending multiple small
> segments.
I agree. But if it breaks the application many people won't be happy,
for example I spend already 5 hours to track it down.
> In the normal case, the extra delay is something like 10 us, so if an
> application is really hit by this delay, its a strong sign it could be
> improved, especially if auto corking is off.
Yes, but 230 micro seconds for others. :-(
> Lets wait the end of 3.14 dev cycle before considering this patch.
I agree.
Btw. I mixed up the pcaps for autocork on and off, so I moved the files
that they know show what they should show.
Cheers,
Thomas
next prev parent reply other threads:[~2014-02-08 16:55 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20140206153640.GB4103@glanzmann.de>
[not found] ` <1391727771.14985.41.camel@haakon3.risingtidesystems.com>
[not found] ` <20140207051500.GB10916@glanzmann.de>
[not found] ` <20140207075536.GB17815@glanzmann.de>
[not found] ` <1391801597.1155.28.camel@haakon3.risingtidesystems.com>
[not found] ` <20140207205142.GA8609@glanzmann.de>
2014-02-08 9:18 ` REGRESSION f54b311142a92ea2e42598e347b84e1655caf8e3 tcp auto corking slows down iSCSI file system creation by factor of 70 [WAS: 4 TB VMFS creation takes 15 minutes vs 26 seconds] Thomas Glanzmann
2014-02-08 9:19 ` [PATCH] tcp: disable auto corking by default Thomas Glanzmann
2014-02-08 15:04 ` Eric Dumazet
2014-02-08 16:55 ` Thomas Glanzmann [this message]
2014-02-08 17:12 ` Eric Dumazet
2014-02-08 17:20 ` Thomas Glanzmann
2014-02-08 9:23 ` REGRESSION f54b311142a92ea2e42598e347b84e1655caf8e3 tcp auto corking slows down iSCSI file system creation by factor of 70 [WAS: 4 TB VMFS creation takes 15 minutes vs 26 seconds] Thomas Glanzmann
2014-02-08 9:38 ` Thomas Glanzmann
2014-02-08 13:14 ` Eric Dumazet
2014-02-08 13:33 ` Eric Dumazet
2014-02-08 13:38 ` Thomas Glanzmann
2014-02-08 13:50 ` Eric Dumazet
2014-02-08 14:13 ` Eric Dumazet
2014-02-08 14:19 ` Thomas Glanzmann
2014-02-08 14:30 ` Eric Dumazet
2014-02-08 15:00 ` Thomas Glanzmann
2014-02-08 15:06 ` Eric Dumazet
2014-02-08 16:57 ` Thomas Glanzmann
2014-02-08 17:08 ` Eric Dumazet
2014-02-08 17:15 ` Thomas Glanzmann
2014-02-08 19:12 ` Eric Dumazet
2014-02-08 21:36 ` Thomas Glanzmann
2014-02-09 0:15 ` Eric Dumazet
2014-02-09 7:45 ` Thomas Glanzmann
2014-02-09 7:40 ` RFC: Set MSG_MORE in iscsit_fe_sendpage_sg to avoid sending multiple TCP packets instead of one Thomas Glanzmann
2014-02-09 7:42 ` [PATCH] This extends tx_data and and iscsit_do_tx_data with the additional parameter flags and avoids sending multiple TCP packets in iscsit_fe_sendpage_sg Eric Dumazet
2014-02-09 12:30 ` Eric Dumazet
2014-02-09 15:07 ` Thomas Glanzmann
2014-02-10 18:58 ` Nicholas A. Bellinger
2014-02-10 20:56 ` Thomas Glanzmann
2014-02-10 21:01 ` Eric Dumazet
2014-02-10 21:14 ` Thomas Glanzmann
2014-02-08 13:37 ` REGRESSION f54b311142a92ea2e42598e347b84e1655caf8e3 tcp auto corking slows down iSCSI file system creation by factor of 70 [WAS: 4 TB VMFS creation takes 15 minutes vs 26 seconds] Thomas Glanzmann
2014-02-08 13:53 ` Eric Dumazet
2014-02-08 13:58 ` Thomas Glanzmann
2014-02-08 14:09 ` Eric Dumazet
2014-02-08 14:12 ` Thomas Glanzmann
2014-02-17 14:08 ` Thomas Glanzmann
2014-02-17 15:26 ` Eric Dumazet
2014-02-17 15:32 ` Thomas Glanzmann
2014-02-17 15:46 ` Eric Dumazet
2014-02-17 15:46 ` Thomas Glanzmann
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