I will do that, won't be until end of next week though when I have
access to it.

> On Jun 19, 2017, at 8:01 AM, Joseph Salisbury 
> <[email protected]> wrote:
> 
> Would it be possible for you to test the latest upstream kernel? Refer
> to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest
> v4.12 kernel[0].
> 
> If this bug is fixed in the mainline kernel, please add the following
> tag 'kernel-fixed-upstream'.
> 
> If the mainline kernel does not fix this bug, please add the tag:
> 'kernel-bug-exists-upstream'.
> 
> Once testing of the upstream kernel is complete, please mark this bug as
> "Confirmed".
> 
> 
> Thanks in advance.
> 
> [0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.12-rc5
> 
> -- 
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1698454
> 
> Title:
>  TCP/IP Throughput Limitation
> 
> Status in linux package in Ubuntu:
>  Incomplete
> 
> Bug description:
>  I'm having a severe TCP receive problem with a new Ubuntu 16 server
>  and an Intel 82599ES 10-Gigabit SFP+ (X520 series card) when a windows
>  10 machine is used to send the data. The receive performance is 1Gb to
>  2Gb steady using iperf single stream, while send is 9.42Gb.
> 
>  Here is what I have found:
> 
>  -Running 8 parallel streams in iperf gets me the full 9.42 in
>  aggregate
> 
>  -Tried a few windows 10 machines with repeatable same results
> 
>  -Same results through switch or direct
> 
>  -Linux to linux no problems
> 
>  -Tested with clean installs of 16.04.02 and 4.4.0-66 kernel, latest
>  the upgrade will give me, also tried 17.04 with up to
>  4.10.0-20-generic same problem, tried 4.11.0-041100rc8-generic and
>  problem seemed to go away for a bit but came back so I think that
>  might be a red herring (see interesting note below).
> 
>  -14.04 and 15.10 with up to 4.2.8-040208-generic is 9.42/9.42 (works
>  fine, couldn't get 4.3 to install on 15.10)
> 
>  -14.04 with the latest 5.0.4 ixgbe driver still works fine, does not
>  seem to be a driver version issue.
> 
>  -Tried swapping out cards with another same model/chipset with same
>  exact result
> 
>  -Large receive offload increases the performance from a steady 1Gb to
>  a steady 2.14Gb
> 
>  -Disabling sack under got me 75% of the way back to full speed, but it
>  was very unstable (didn't hold at a solid speed)
> 
>  -Using a different brand of card in this same server (but not the same
>  slot) (mellanox infiniband running in ethernet mode) is 9.42/8.5
>  (seems to work fine, 9.42 to 8.5 is windows machine limit I think)
> 
>  -Interesting: When swapping between intel and mellanox 10Gbe cards
>  (with a reboot of the server inbetween, but not a reboot of the
>  windows machine, and keeping the same IP on the server) the
>  performance does not change immediately. When going from intel to
>  mellanox the first test holds around 1 or 2Gbit, then after that it
>  jumps up to 8.5 steady. Similarly when switching from mellanox to
>  Intel the first 1 or 2 seconds of performance hits 8.x then drop in
>  half or more and within 3 or 4 seconds it is back to 1Gbit and stays
>  there for each subsequent iperf test.
> 
>  -Interesting: When capturing packets on wireshark on windows,
>  performance comes up to 8.5! (No, ditching windows isn't an option
>  here unfortunately. :) So obviously something in the way the two tcp
>  stacks are interacting without a buffer inbetween when the intel
>  driver is online is causing issues.
> 
>  -Port bonding makes no difference (nor should it for single stream)
> 
>  -Tried rolling the intel driver back to the 3.2.1 version that is on
>  14.04 but it was too old to compile
> 
>  -I suspect this is a kernel TCP/IP implementation change somewhere
>  between 4.2 and 4.4 that has caused it to not play nice with window's
>  stack.  Based on the delayed performance change I'm thinking something
>  is messing with flow control, the tcp congestion algorithm, or the tcp
>  window. I tried turning some various tcp options off, tweaking some
>  values, changing congestion algorithms, hardware flow control, and
>  comparing sysctl stuff from the u14 machine to this machine to no
>  avail.
> 
> To manage notifications about this bug go to:
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Title:
  TCP/IP Throughput Limitation

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