From: Hannes Frederic Sowa <hannes@stressinduktion.org>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Francois WELLENREITER <f.wellenreiter@gmail.com>, netdev@vger.kernel.org
Subject: Re: Does IPv6 support Jumbograms ?
Date: Thu, 10 Apr 2014 00:35:46 +0200 [thread overview]
Message-ID: <20140409223546.GH27255@order.stressinduktion.org> (raw)
In-Reply-To: <1397079665.16584.17.camel@edumazet-glaptop2.roam.corp.google.com>
On Wed, Apr 09, 2014 at 02:41:05PM -0700, Eric Dumazet wrote:
> On Wed, 2014-04-09 at 21:42 +0200, Francois WELLENREITER wrote:
> > Hi there,
> >
> > I've been recently running performance tests with the loopback interface
> > increasing the MTU over the 65535 byte limit.
> > I was really surprised to see that a simple scp onto the ::1 address
> > systematically blocked after transferring about 2,4 MB.
> > My interpretation of this behavior is that the current IPv6 kernel layer
> > does not support Jumbograms at all. Am I wrong ?
> > If that's not the case, what could then the right interpretation of this
> > issue ?
> > And whenever I'm right, is there any plan to support this feature in a
> > near future ?
>
> What do you mean by blocked ?
>
> Please give more details (kernel version, exact mtu...), because it
> should not happen !
>
> # ifconfig lo mtu 100000
> # scp -6 vmlinux edumazet@ip6-localhost:/tmp
> Password:
> vmlinux
> 100% 24MB 23.5MB/s 00:00
> # ls -l /tmp/vmlinux
> -rwxr-xr-x 1 edumazet eng 24668915 Apr 9 14:37 /tmp/vmlinux
I couldn't test it on my development system with a recent net-next kernel
yet, but on my laptop with a distribution 3.13.9 kernel this happened too.
I tested with two netcats and threw a dd from /dev/zero into it with a
1MB block size. ssh seems not to be aggressive enough to trigger this:
# tcpdump -i lo -vvv -nKS tcp and port 9988
# tcpdump -i lo -nKS -vvv tcp and port 9988
tcpdump: listening on lo, link-type EN10MB (Ethernet), capture size 65535 bytes
00:26:02.914511 IP6 (hlim 64, next-header TCP (6) payload length: 40) ::1.52141 > ::1.nsesrvr: Flags [S], seq 2750352628, win 43690, options [mss 65535,sackOK,TS val 43288646 ecr 0,nop,wscale 7], length 0
00:26:02.914593 IP6 (hlim 64, next-header TCP (6) payload length: 40) ::1.nsesrvr > ::1.52141: Flags [S.], seq 1418051855, ack 2750352629, win 43690, options [mss 65535,sackOK,TS val 43288647 ecr 43288646,nop,wscale 7], length 0
00:26:02.914659 IP6 (hlim 64, next-header TCP (6) payload length: 32) ::1.52141 > ::1.nsesrvr: Flags [.], seq 2750352629, ack 1418051856, win 342, options [nop,nop,TS val 43288647 ecr 43288647], length 0
00:26:02.915013 IP6 (hlim 64, next-header TCP (6) payload length: 8224) ::1.52141 > ::1.nsesrvr: Flags [P.], seq 2750352629:2750360821, ack 1418051856, win 342, options [nop,nop,TS val 43288647 ecr 43288647], length 8192
00:26:02.915089 IP6 (hlim 64, next-header TCP (6) payload length: 32) ::1.nsesrvr > ::1.52141: Flags [.], seq 1418051856, ack 2750360821, win 1366, options [nop,nop,TS val 43288647 ecr 43288647], length 0
00:26:02.915289 IP6 (hlim 64, next-header TCP (6) payload length: 8224) ::1.52141 > ::1.nsesrvr: Flags [P.], seq 2750360821:2750369013, ack 1418051856, win 342, options [nop,nop,TS val 43288647 ecr 43288647], length 8192
00:26:02.915342 IP6 (hlim 64, next-header TCP (6) payload length: 32) ::1.nsesrvr > ::1.52141: Flags [.], seq 1418051856, ack 2750369013, win 2389, options [nop,nop,TS val 43288647 ecr 43288647], length 0
00:26:02.915467 IP6 (hlim 64, next-header TCP (6) payload length: 8224) ::1.52141 > ::1.nsesrvr: Flags [P.], seq 2750369013:2750377205, ack 1418051856, win 342, options [nop,nop,TS val 43288647 ecr 43288647], length 8192
00:26:02.915558 IP6 (hlim 64, next-header TCP (6) payload length: 32) ::1.nsesrvr > ::1.52141: Flags [.], seq 1418051856, ack 2750377205, win 3413, options [nop,nop,TS val 43288648 ecr 43288647], length 0
00:26:02.915723 IP6 (hlim 64, next-header TCP (6) payload length: 8224) ::1.52141 > ::1.nsesrvr: Flags [P.], seq 2750377205:2750385397, ack 1418051856, win 342, options [nop,nop,TS val 43288648 ecr 43288648], length 8192
00:26:02.915778 IP6 (hlim 64, next-header TCP (6) payload length: 32) ::1.nsesrvr > ::1.52141: Flags [.], seq 1418051856, ack 2750385397, win 3639, options [nop,nop,TS val 43288648 ecr 43288648], length 0
00:26:02.915898 IP6 (hlim 64, next-header TCP (6) payload length: 8224) ::1.52141 > ::1.nsesrvr: Flags [P.], seq 2750385397:2750393589, ack 1418051856, win 342, options [nop,nop,TS val 43288648 ecr 43288648], length 8192
00:26:02.915952 IP6 (hlim 64, next-header TCP (6) payload length: 32) ::1.nsesrvr > ::1.52141: Flags [.], seq 1418051856, ack 2750393589, win 3639, options [nop,nop,TS val 43288648 ecr 43288648], length 0
00:26:02.916072 IP6 (hlim 64, next-header TCP (6) payload length: 8224) ::1.52141 > ::1.nsesrvr: Flags [P.], seq 2750393589:2750401781, ack 1418051856, win 342, options [nop,nop,TS val 43288648 ecr 43288648], length 8192
00:26:02.916126 IP6 (hlim 64, next-header TCP (6) payload length: 32) ::1.nsesrvr > ::1.52141: Flags [.], seq 1418051856, ack 2750401781, win 3639, options [nop,nop,TS val 43288648 ecr 43288648], length 0
00:26:02.916245 IP6 (hlim 64, next-header TCP (6) payload length: 8224) ::1.52141 > ::1.nsesrvr: Flags [P.], seq 2750401781:2750409973, ack 1418051856, win 342, options [nop,nop,TS val 43288648 ecr 43288648], length 8192
00:26:02.916850 IP6 (hlim 64, next-header TCP (6) payload length: 19) ::1.52141 > ::1.nsesrvr: [|tcp]
00:26:02.918682 IP6 (hlim 64, next-header TCP (6) payload length: 19) ::1.52141 > ::1.nsesrvr: [|tcp]
00:26:02.919852 IP6 (hlim 64, next-header TCP (6) payload length: 19) ::1.52141 > ::1.nsesrvr: [|tcp]
00:26:02.920966 IP6 (hlim 64, next-header TCP (6) payload length: 19) ::1.52141 > ::1.nsesrvr: [|tcp]
00:26:02.922092 IP6 (hlim 64, next-header TCP (6) payload length: 19) ::1.52141 > ::1.nsesrvr: [|tcp]
00:26:02.923194 IP6 (hlim 64, next-header TCP (6) payload length: 19) ::1.52141 > ::1.nsesrvr: [|tcp]
00:26:02.955634 IP6 (hlim 64, next-header TCP (6) payload length: 32) ::1.nsesrvr > ::1.52141: Flags [.], seq 1418051856, ack 2750409973, win 3639, options [nop,nop,TS val 43288688 ecr 43288648], length 0
00:26:02.955832 IP6 (hlim 64, next-header TCP (6) payload length: 19) ::1.52141 > ::1.nsesrvr: [|tcp]
00:26:03.160698 IP6 (hlim 64, next-header TCP (6) payload length: 19) ::1.52141 > ::1.nsesrvr: [|tcp]
00:26:03.572148 IP6 (hlim 64, next-header TCP (6) payload length: 19) ::1.52141 > ::1.nsesrvr: [|tcp]
00:26:04.394117 IP6 (hlim 64, next-header TCP (6) payload length: 19) ::1.52141 > ::1.nsesrvr: [|tcp]
Hmm... that is strange.
Bye,
Hannes
next prev parent reply other threads:[~2014-04-09 22:35 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-09 19:42 Does IPv6 support Jumbograms ? Francois WELLENREITER
2014-04-09 20:35 ` Hannes Frederic Sowa
2014-04-09 21:41 ` Eric Dumazet
2014-04-09 22:35 ` Hannes Frederic Sowa [this message]
2014-04-10 0:36 ` Eric Dumazet
2014-04-10 13:28 ` Hannes Frederic Sowa
2014-04-10 14:01 ` Eric Dumazet
2014-04-10 23:54 ` Hannes Frederic Sowa
2014-04-11 0:40 ` Eric Dumazet
2014-04-11 1:42 ` [PATCH] ipv6: Limit mtu to 65572 bytes Eric Dumazet
2014-04-11 1:58 ` Eric Dumazet
2014-04-11 2:30 ` YOSHIFUJI Hideaki
2014-04-11 2:57 ` Hannes Frederic Sowa
2014-04-11 3:14 ` Eric Dumazet
2014-04-11 8:40 ` David Laight
2014-04-11 8:34 ` David Laight
2014-04-11 3:20 ` Eric Dumazet
2014-04-11 3:26 ` YOSHIFUJI Hideaki
2014-04-11 3:30 ` YOSHIFUJI Hideaki
2014-04-11 3:30 ` David Miller
2014-04-11 4:20 ` Eric Dumazet
2014-04-11 4:23 ` [PATCH v3] ipv6: Limit mtu to 65575 bytes Eric Dumazet
2014-04-11 13:22 ` Hannes Frederic Sowa
2014-04-11 15:26 ` Eric Dumazet
2014-04-11 20:48 ` David Miller
2014-04-11 2:44 ` [PATCH] ipv6: Limit mtu to 65572 bytes Hannes Frederic Sowa
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